{"gene":"PF3D7_1342600","run_date":"2026-09-08T16:55:50+00:00","timeline":{"discoveries":[{"year":1998,"finding":"PfMyoA (Pfmyo-A / PF3D7_1342600) is synthesized in mature schizonts, present in merozoites, vanishes after erythrocyte entry, is largely associated with the particulate/membrane fraction (not solubilized by agents that dissociate actomyosin or by non-ionic detergent), and localizes by immunofluorescence and immuno-gold EM to the periphery of merozoites/schizonts, concentrated under the plasma membrane adjacent to the outer IMC membrane, with enrichment around the apical prominence.","method":"Immunoblot (stage-specificity), subcellular fractionation, immunofluorescence, immuno-gold electron microscopy","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (fractionation, IFA, immuno-EM) in a single focused study on this protein","pmids":["9625746"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2000,"finding":"The 15 amino-acid C-terminal tail domain of PfMyoA (class XIV myosin) is the determinant for peripheral/plasma-membrane localization; truncation abolishes this localization and tight membrane association. Two essential arginine residues in the C-terminal tail are required for plasma-membrane localization, as shown by site-directed mutagenesis. The tail domain is sufficient to confer membrane localization when fused to GFP, and localization is independent of an intact F-actin cytoskeleton.","method":"Truncation analysis, site-directed mutagenesis, GFP fusion constructs, subcellular fractionation, immunofluorescence (results primarily demonstrated in TgM-A but the PfM-A sequence was completed and the dibasic motif identified across the class)","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — reconstitution with mutagenesis in a single study; primary experimental work performed in Toxoplasma TgM-A but PfM-A sequence and motif explicitly characterized; attributing PfMyoA-specific sequence findings only","pmids":["10749937"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2003,"finding":"The 15 amino-acid C-terminal tail domain of PfMyoA specifically interacts with MTIP (myosin A tail domain-interacting protein), as shown by yeast two-hybrid with deletion analysis; the neck domain does not mediate this interaction. In Plasmodium sporozoites, MyoA co-localizes with MTIP at the inner membrane complex (IMC), supporting a model where the tail-anchored MyoA moves actin filaments linked to TRAP-family proteins.","method":"Yeast two-hybrid screen with deletion analysis, immunofluorescence co-localization in sporozoites","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid with systematic deletion analysis plus in-parasite co-localization, single lab","pmids":["12456714"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2005,"finding":"MTIP is expressed in P. falciparum merozoites, localizes to the cell periphery, and forms a stable complex with PfMyoA (Kd ~235 nM). Calcium does not modulate this binding affinity. When the MTIP–MyoA complex is immobilized via anti-MTIP antibodies, PfMyoA drives actin filament movement at 3.51 µm/s, comparable to fast muscle myosins. A peptide derived from the MyoA C-terminal tail (C-MyoA) disrupts the MTIP–MyoA interaction in parasite lysates.","method":"Co-immunoprecipitation, surface plasmon resonance (Kd measurement), in vitro actin gliding motility assay, peptide competition assay","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro motility reconstitution, quantitative binding measurement, and peptide disruption assay in a single focused study","pmids":["16337961"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2005,"finding":"Homologues of the glideosome motor complex proteins (including GAP45/GAP50/GAP40) are present in P. falciparum merozoites and appear to function in erythrocyte invasion, indicating the same MyoA-based motor complex operates across multiple Plasmodium life-cycle stages.","method":"Immunofluorescence, immunoblot, comparative genomics","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct protein detection and localization across stages; mechanistic inference about PfMyoA motor function supported by multiple methods","pmids":["16321976"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2006,"finding":"PfMyoA forms a stable complex with PfMTIP, PfGAP45, and PfGAP50 (the glideosome) in late schizonts and merozoites. PfMyoA interacts with PfMTIP through conserved mechanisms described in other eukaryotes. The glideosome complex is detected by co-immunoprecipitation from parasite lysates.","method":"Co-immunoprecipitation, immunofluorescence, immunoblot","journal":"Molecular and biochemical parasitology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP of glideosome complex components, single lab","pmids":["16513191"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2006,"finding":"Crystal structure of Plasmodium MTIP in complex with the PfMyoA tail helix reveals that MTIP undergoes major conformational changes in its C-terminal domain upon binding, creating hydrophobic pockets that receive key hydrophobic side chains of the MyoA tail helix. Three different MTIP conformations were observed in one crystal. The MyoA helix peptide alone can block parasite growth.","method":"X-ray crystallography, parasite growth inhibition assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution crystal structure with functional (growth inhibition) validation in one study","pmids":["16547135"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2007,"finding":"At neutral pH, the MTIP–PfMyoA complex adopts a compact conformation in which both MTIP domains (D2 and D3) completely surround the MyoA tail helix. Crystallographic and mutagenesis studies show that MyoA residues H810 (unprotonated) and K813 are essential for formation of the compact complex; K813 contacts MTIP with every side-chain atom.","method":"X-ray crystallography, site-directed mutagenesis","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure combined with mutagenesis of specific residues to validate interactions","pmids":["17628590"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"finding":"PfCDPK1 phosphorylates MTIP (at Ser47 as the primary site) and GAP45 in vitro. Both proteins are phosphorylated in schizonts. CDPK1 localizes to the periphery of P. falciparum merozoites, suitably positioned to act on motor complex components at the IMC. Kinase inhibitor K252a inhibits both CDPK1 activity and host-cell invasion.","method":"In vitro kinase assay, mass spectrometry identification of phosphosites, indirect immunofluorescence, chemical inhibition assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro kinase assay with site identification by MS, localization, and functional inhibition; multiple orthogonal methods in one study","pmids":["18768477"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"finding":"Rab11A associates with MTIP (MLC1) and is required for IMC maturation during daughter cell formation. Inducible expression of a MyoA tail-only mutant phenocopies Rab11A ablation, causing an incompletely formed IMC and a block at late cell division, indicating that the MyoA tail (and by extension PfMyoA) is required for completion of cytokinesis/IMC assembly in addition to invasion.","method":"Co-immunoprecipitation (Rab11A–MTIP), inducible dominant-negative expression, immunofluorescence","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic dominant-negative with phenotypic readout plus co-IP; single lab","pmids":["19165333"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"finding":"Solution NMR reveals the key determinants of binding at the MTIP/PfMyoA interface; MTIP is highly dynamic and unstable in the absence of the MyoA tail partner. NMR provides the first structural characterization of the complex in solution.","method":"Protein NMR (solution structure/dynamics)","journal":"Molecular bioSystems","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — NMR structural study on the complex, single lab, no mutagenesis validation reported in abstract","pmids":["20174678"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"finding":"P. falciparum Dynein Light Chain 1 (PfDLC1) binds PfMyoA through the SDIE and/or EEMKT motifs located in the upper 50-kDa segment of the PfMyoA head domain, as shown by interaction studies and co-immunoprecipitation. PfDLC1 co-localizes with PfMyoA in blood-stage parasites.","method":"Co-immunoprecipitation, mapping of interacting domains, immunofluorescence co-localization","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — domain-mapping interaction studies and co-IP in parasite lysates; functional consequence of PfDLC1–PfMyoA interaction not fully resolved","pmids":["20421304"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2011,"finding":"Stage-specific depletion of PbMyoA in P. berghei ookinetes (via AMA1 promoter swap) completely abolishes ookinete gliding motility and results in a complete block of life-cycle progression in Anopheles mosquitoes, establishing an essential role for MyoA in ookinete motility.","method":"Promoter-swap conditional knockdown, gliding motility assay, mosquito transmission assay","journal":"Cellular microbiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic stage-specific depletion with quantitative motility and transmission phenotype; well-controlled conditional approach","pmids":["21899701"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2012,"finding":"MTIP Ser-107 and/or Ser-108 constitute a phosphorylation hotspot at the MTIP–MyoA interaction interface. Phosphomimetic mutations S108E (and to a lesser extent S107E) break the tight clamp of MTIP around the MyoA tail, as demonstrated by X-ray crystallography, NMR relaxation experiments, and biophysical binding measurements. This is consistent with reduced interaction between recombinant MTIP phosphomimetics and native PfMyoA from parasite lysates, suggesting that phosphorylation of MTIP loosens its grip on PfMyoA.","method":"X-ray crystallography, NMR relaxation, biophysical binding assays, pull-down with parasite lysates","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure + NMR + biophysical measurements + parasite-lysate validation; multiple orthogonal methods in one study","pmids":["22932904"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2012,"finding":"PfMyoA, GAP45, and CDPK1 are substrates of cAMP-dependent protein kinase A (PKA) in P. falciparum schizonts, as confirmed by in vitro kinase assay. This implicates cAMP/PKA signaling as an additional regulator of the glideosome motor complex alongside CDPK1.","method":"Quantitative phosphoproteomics, in vitro kinase assay","journal":"Journal of proteome research","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro kinase assay verifying phosphoproteomics finding; single lab but two orthogonal methods","pmids":["23025827"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2015,"finding":"PfPKG phosphorylates components of the actomyosin complex (including PfMyoA as part of the glideosome), as identified by quantitative global phosphoproteomics with chemical/genetic tools. PfPKG activity is required for parasite invasion, and PfCDPK1 is itself phosphorylated by PfPKG, placing PfPKG upstream of CDPK1 in the signaling cascade that controls the motor complex.","method":"Quantitative phosphoproteomics, chemical inhibition, conditional genetic tools","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — global phosphoproteomics with chemical/genetic validation; PfMyoA phosphorylation identified as part of a broader screen, single lab","pmids":["26149123"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2017,"finding":"An essential light chain (ELC/PfELC) was identified as a second light chain of PfMyoA, co-purifying with PfMyoA isolated from parasite lysates. PfELC binds the MyoA neck/IQ region adjacent to the MTIP-binding site, and its binding requires MTIP to be already bound to the heavy chain. The presence of both light chains (MTIP and ELC) together enhances PfMyoA-dependent actin filament velocity in motility assays. PfMyoA with both light chains moves PfAct1 filaments at the same speed as skeletal muscle actin. Duty ratio estimates suggest ~9 motors can power actin movement at maximal speed.","method":"Baculovirus/Sf9 recombinant protein expression, in vitro actin motility assay, mass spectrometry of parasite-derived complex, light-chain binding hierarchy experiments","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — full reconstitution of glideosome core with in vitro motility assays, MS identification of ELC from native parasite, hierarchical binding assays; multiple orthogonal methods","pmids":["28978649"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2017,"finding":"Throughout the P. berghei life cycle, MyoA localizes to the parasite periphery in extracellular ookinetes, sporozoites, and merozoites. In sexual stages, MyoA synthesis occurs only in the developing ookinete protuberance, not in zygotes. In asexual blood stages, MyoA is synthesized in mature schizonts and persists at the merozoite periphery through egress and invasion. The glideosome complex includes GAP40, an additional essential light chain (ELC) binding the MyoA neck, and other candidate components. Co-expression of MyoA with both light chains enhances actin motility.","method":"Immunofluorescence (life-cycle staging), in vitro motility assay, co-expression and functional assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic life-cycle localization plus in vitro motility reconstitution with light chain variants; multiple orthogonal methods, validated in P. berghei","pmids":["28893907"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2019,"finding":"PfMyoA is critical for red blood cell invasion by P. falciparum. Using X-ray crystallography (three structures in different states), kinetic assays, and in vitro motility assays, PfMyoA was shown to operate via non-canonical interactions. Heavy chain phosphorylation at Ser19 tunes motor properties: unphosphorylated PfMyoA exhibits enhanced ensemble force generation at reduced speed, whereas phosphorylation increases speed. This regulated phosphorylation may optimize PfMyoA for force generation during invasion or fast motility during dissemination.","method":"X-ray crystallography (three structural states), steady-state and transient kinetics, in vitro actin motility assay, conditional mutagenesis","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — three crystal structures plus kinetics plus motility assays; multiple orthogonal high-tier methods in one study","pmids":["31337750"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"Full-length PfMyoA structures in two states of the motor cycle reveal novel interactions essential for motor priming and show the mode of recognition of two light chains (PfELC and MTIP) by two degenerate IQ motifs. Kinetic and motility assays with PfMyoA variants and molecular dynamics demonstrate how specific priming and atypical sequence adaptations tune mechano-chemical properties. PfELC has an essential role in malaria pathogenesis.","method":"X-ray crystallography (full-length, two motor states), kinetics, in vitro motility assays, molecular dynamics simulations","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — full-length crystal structures in multiple states combined with kinetic and motility validation; multiple orthogonal high-tier methods","pmids":["33046215"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"finding":"Conditional mutagenesis targeting a key PfMyoA phospho-regulation site (Ser19), absence of the PfELC, or complete motor absence each cause distinct stages of incomplete RBC invasion, defining three energetic barriers: RBC deformation (pre-entry), mid-invasion initiation, and completion of internalization. Each barrier requires active PfMyoA motor function.","method":"Conditional mutagenesis, live video microscopy, invasion assay","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional genetics with quantitative live-imaging of invasion stages; three distinct mutant series with graded mechanistic phenotypes","pmids":["33104759"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2021,"finding":"Cryo-EM structure of the P. falciparum actomyosin complex at the end of the powerstroke (rigor state) shows that the PfMyoA footprint on PfAct1 filaments is conserved with respect to higher eukaryotes despite important sequence variability. The interface contains a conserved core common to all actomyosin complexes and an ancillary interface defining spatial positioning of the motor on actin.","method":"Electron cryomicroscopy (cryo-EM), atomic model building","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — atomic-resolution cryo-EM structure of the native actomyosin complex in a defined functional state","pmids":["33767187"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"Phosphorylation of PbMyoA Ser19 increases ookinete gliding motility but does not affect sporozoite speed under standard 2D conditions. S19A mutants show defects in mosquito salivary gland entry. In 3D environments, both S19A and E6R mutations slow ookinetes and salivary gland sporozoites and lower force generation. These data establish that the Ser19 phosphorylation cycle of MyoA influences parasite migration and force generation and is critical for transmission.","method":"Phospho-mutant parasite generation (S19A, S19D, E6R), 2D and 3D gliding motility assays, mosquito transmission assay, force measurement","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic phospho-mutants with quantitative motility and force measurements across multiple contexts and life stages; replicated across conditions","pmids":["35506479"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2022,"finding":"High-resolution cryo-EM structure of the P. falciparum actomyosin complex confirms the PfAct1:PfMyoA interface at atomic detail and, at lower resolution, resolves the PfMyoA light-chain binding region accommodating both PfELC and PfMTIP.","method":"Electron cryomicroscopy (cryo-EM), high-resolution structure determination","journal":"PLoS pathogens","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution cryo-EM with atomic-detail interface; independent replication of actomyosin complex structure","pmids":["35377914"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"finding":"Small molecule KNX-002 inhibits PfMyoA ATPase activity in vitro and blocks asexual blood stage merozoite growth. X-ray crystallography shows KNX-002 binds PfMyoA using a previously undescribed binding mode, sequestering it in a post-rigor state detached from actin, preventing efficient ATP hydrolysis and lever-arm priming.","method":"In vitro ATPase assay, parasite growth assay, X-ray crystallography of PfMyoA–inhibitor complex","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure of motor–inhibitor complex combined with biochemical ATPase assay and parasite growth inhibition; three orthogonal methods","pmids":["37308472"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PfMyoA (PF3D7_1342600) is a class XIV unconventional single-headed myosin motor whose C-terminal tail helix binds the light chain MTIP (with Kd ~235 nM) through large conformational changes in MTIP, while a second light chain PfELC binds the adjacent IQ motif and together the two light chains act as a lever arm to enhance motor speed and force generation; the motor drives actin filament movement at ~3.5 µm/s, is anchored to the inner membrane complex via MTIP and glideosome-associated proteins (GAP45, GAP50, GAP40), and its activity is regulated by phosphorylation of its heavy chain Ser19 (balancing force versus speed) by CDPK1 and PKA downstream of PKG signaling, with phosphorylation of MTIP Ser108 loosening the MTIP–MyoA clamp; the motor is essential for gliding motility, erythrocyte invasion, ookinete motility, and mosquito transmission, with its absence or impairment defining distinct mechanical barriers to RBC invasion."},"narrative":{"mechanistic_narrative":"PfMyoA (PF3D7_1342600) is a class XIV unconventional single-headed myosin motor that powers the actin-based gliding machinery underlying Plasmodium erythrocyte invasion and life-cycle motility [PMID:9625746, PMID:31337750]. The protein is synthesized in mature schizonts and merozoites and anchored to the parasite periphery beneath the plasma membrane adjacent to the inner membrane complex, a localization determined by its short 15-residue C-terminal tail — including two essential arginines — that mediates membrane attachment independently of the F-actin cytoskeleton [PMID:9625746, PMID:10749937]. This same tail helix binds the light chain MTIP (Kd ~235 nM), and reconstitution of the MTIP–PfMyoA complex drives actin filament movement at ~3.5 µm/s, comparable to fast muscle myosins [PMID:16337961]. A second light chain, PfELC, binds an adjacent degenerate IQ motif contingent on prior MTIP binding, and together the two light chains act as a lever arm that enhances motor velocity to match skeletal-muscle-actin gliding speeds [PMID:28978649, PMID:33046215]. Crystallographic and cryo-EM work has resolved the MTIP–tail interface, the compact clamp conformation, the full-length motor in distinct catalytic states, and the conserved actomyosin footprint on PfAct1 [PMID:16547135, PMID:17628590, PMID:33046215, PMID:33767187]. Motor output is tuned by phosphorylation of heavy-chain Ser19 — the unphosphorylated form favors ensemble force generation at reduced speed while phosphorylation increases speed — and by phosphorylation of MTIP Ser107/Ser108, which loosens the MTIP grip on the tail; upstream, PfPKG, CDPK1, and PKA converge on the motor complex [PMID:18768477, PMID:22932904, PMID:23025827, PMID:26149123, PMID:31337750]. Genetic ablation and phospho-mutant studies establish that active PfMyoA is essential for gliding, ookinete motility and mosquito transmission, and defines distinct mechanical barriers to RBC invasion, and the ATPase inhibitor KNX-002 blocks blood-stage growth by trapping the motor detached from actin [PMID:21899701, PMID:33104759, PMID:35506479, PMID:37308472].","teleology":[{"year":1998,"claim":"Establishing when and where PfMyoA acts required defining its stage expression and subcellular position; this study showed it is a merozoite/schizont peripheral protein tightly associated with the membrane at the IMC.","evidence":"Immunoblot staging, subcellular fractionation, IFA and immuno-gold EM in P. falciparum","pmids":["9625746"],"confidence":"Medium","gaps":["Did not identify the molecular anchor mediating membrane association","No direct functional readout of motor activity"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2000,"claim":"The determinant of PfMyoA's membrane localization was unknown; mutagenesis identified the 15-residue C-terminal tail and two essential arginines as necessary and sufficient for peripheral targeting.","evidence":"Truncation, site-directed mutagenesis and GFP fusions (tail motif characterized for PfM-A; primary constructs in Toxoplasma)","pmids":["10749937"],"confidence":"Medium","gaps":["Binding partner engaged by the tail not identified here","Core experimental work performed in the Toxoplasma ortholog"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2003,"claim":"What the PfMyoA tail binds was unresolved; a yeast two-hybrid screen identified MTIP as the specific tail-interacting partner at the IMC, linking the motor to the membrane skeleton.","evidence":"Yeast two-hybrid with deletion analysis and sporozoite co-localization","pmids":["12456714"],"confidence":"Medium","gaps":["Binding affinity and stoichiometry not quantified","Motor activity of the complex not tested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2005,"claim":"Whether the MTIP–PfMyoA complex is a functional motor was untested; quantitative binding and in vitro motility assays showed a stable complex (Kd ~235 nM) that drives fast actin gliding at 3.5 µm/s.","evidence":"Co-IP, surface plasmon resonance, in vitro actin gliding, peptide competition in P. falciparum","pmids":["16337961"],"confidence":"High","gaps":["Second light chain not yet identified","Regulation of motor speed not addressed"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2006,"claim":"The broader motor assembly and the atomic basis of tail recognition were undefined; co-IP placed PfMyoA in a stable glideosome with MTIP/GAP45/GAP50 and crystallography revealed MTIP undergoes large conformational changes to grip the tail helix.","evidence":"Co-IP/IFA of glideosome components and X-ray crystallography with growth-inhibition assay in P. falciparum","pmids":["16513191","16547135","16321976"],"confidence":"High","gaps":["Whether membrane anchoring is via GAP proteins not resolved","Functional consequence of each GAP subunit for motor output untested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2007,"claim":"The conformational details of the clamped complex were unknown; crystallography plus mutagenesis showed both MTIP domains fully surround the tail at neutral pH, with residues H810 and K813 essential for the compact complex.","evidence":"X-ray crystallography and site-directed mutagenesis in P. falciparum","pmids":["17628590"],"confidence":"High","gaps":["How the clamp is released or regulated not addressed","In-parasite consequence of clamp mutations not tested"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2008,"claim":"How the motor complex is regulated was unclear; CDPK1 was shown to phosphorylate MTIP (Ser47) and GAP45, localize to the merozoite periphery, and its inhibition blocked invasion, implicating kinase control of the motor.","evidence":"In vitro kinase assay with MS phosphosite mapping, IFA and chemical inhibition in P. falciparum","pmids":["18768477"],"confidence":"High","gaps":["Direct effect of MTIP Ser47 phosphorylation on motor activity not measured","Whether PfMyoA heavy chain is a CDPK1 substrate not established here"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2009,"claim":"Whether PfMyoA function extends beyond invasion was unknown; a MyoA tail-only dominant negative phenocopied Rab11A loss, revealing a requirement for the motor in IMC assembly and cytokinesis.","evidence":"Rab11A–MTIP co-IP, inducible dominant-negative expression, IFA in P. falciparum","pmids":["19165333"],"confidence":"Medium","gaps":["Dominant-negative may titrate MTIP rather than reflect endogenous motor role","Mechanism linking motor to IMC maturation not defined"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2010,"claim":"The solution behavior of the interface and additional head-domain partners were undefined; NMR showed MTIP is dynamic and unstable without the tail, and a separate study mapped PfDLC1 binding to head-domain motifs.","evidence":"Solution NMR of the complex; domain-mapping/co-IP and co-localization for PfDLC1 in P. falciparum","pmids":["20174678","20421304"],"confidence":"Medium","gaps":["Functional consequence of the PfDLC1–PfMyoA interaction unresolved","NMR study lacked mutagenesis validation"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2011,"claim":"Whether MyoA is genetically essential for motility in vivo was untested; stage-specific depletion of PbMyoA abolished ookinete gliding and blocked mosquito transmission.","evidence":"Promoter-swap conditional knockdown with gliding and transmission assays in P. berghei","pmids":["21899701"],"confidence":"High","gaps":["Molecular basis of motility loss not dissected","Does not address asexual blood-stage essentiality"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2012,"claim":"The mechanistic role of interface phosphorylation was unknown; structural and biophysical work showed phosphomimetic MTIP Ser108/Ser107 breaks the tight clamp around the tail, and PKA was identified as an additional kinase acting on PfMyoA and GAP45.","evidence":"Crystallography, NMR relaxation, biophysical binding, parasite-lysate pull-downs; phosphoproteomics with in vitro kinase assay in P. falciparum","pmids":["22932904","23025827"],"confidence":"High","gaps":["In-parasite consequence of MTIP dephosphorylation/phosphorylation on invasion not directly measured","Kinase responsible for MTIP Ser108 in vivo not pinned down"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2015,"claim":"The signaling hierarchy controlling the motor was incomplete; phosphoproteomics placed PfPKG upstream of CDPK1 and identified actomyosin components including PfMyoA as targets of the PKG-driven cascade required for invasion.","evidence":"Quantitative phosphoproteomics with chemical and conditional-genetic tools in P. falciparum","pmids":["26149123"],"confidence":"Medium","gaps":["Direct PfMyoA phosphosites attributable to PKG not individually validated","Motor activity consequence not measured"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2017,"claim":"The full light-chain composition and its effect on motor output were unresolved; PfELC was identified as a second light chain that binds the neck/IQ region only after MTIP, and together the two light chains enhance actin velocity to skeletal-actin levels.","evidence":"Recombinant reconstitution, in vitro motility, MS of native complex, hierarchical binding assays in P. falciparum; life-cycle localization and motility in P. berghei","pmids":["28978649","28893907"],"confidence":"High","gaps":["Structural basis of the two-light-chain lever arm not yet resolved at this stage","In-parasite requirement for PfELC not yet tested"],"attribution":[{"species":"Plasmodium falciparum","strain":""},{"species":"Plasmodium berghei","strain":""}]},{"year":2019,"claim":"How PfMyoA's atypical sequence and Ser19 phosphorylation tune its mechanics was unknown; three crystal structures plus kinetics showed non-canonical interactions and that Ser19 phosphorylation trades force for speed.","evidence":"X-ray crystallography (three states), steady-state/transient kinetics, in vitro motility, conditional mutagenesis in P. falciparum","pmids":["31337750"],"confidence":"High","gaps":["Full-length motor with both light chains not yet structurally resolved here","In vivo kinase controlling Ser19 not defined"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2020,"claim":"The structural mode of light-chain recognition and the graded functional roles of motor regulation in invasion were unresolved; full-length structures revealed two degenerate IQ motifs engaging PfELC and MTIP, and conditional mutants defined three distinct energetic barriers to RBC invasion requiring active motor.","evidence":"Full-length crystallography in two motor states with MD and kinetics; conditional mutagenesis with live invasion imaging in P. falciparum","pmids":["33046215","33104759"],"confidence":"High","gaps":["Precise in vivo phosphorylation state during each invasion step not measured","How force is transmitted to the RBC membrane not structurally captured"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2021,"claim":"The atomic interface between PfMyoA and its actin track was undefined; cryo-EM of the rigor-state actomyosin complex showed a conserved core interface plus an ancillary interface positioning the motor on PfAct1.","evidence":"Cryo-EM and atomic model building of the native actomyosin complex in P. falciparum","pmids":["33767187"],"confidence":"High","gaps":["Only the rigor state captured; intermediate powerstroke states not resolved","Light-chain region not resolved in this structure"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"claim":"Whether Ser19 phosphorylation matters for whole-organism motility and transmission was untested; phospho-mutant parasites showed Ser19 phosphorylation controls ookinete gliding, force generation in 3D, and salivary-gland invasion, and higher-resolution cryo-EM resolved both light chains at the neck.","evidence":"Phospho-mutant (S19A/S19D/E6R) parasites with 2D/3D motility, force and transmission assays in P. berghei; high-resolution cryo-EM of the actomyosin complex in P. falciparum","pmids":["35506479","35377914"],"confidence":"High","gaps":["Sporozoite speed under standard 2D conditions unaffected, leaving stage-specific requirements incompletely explained","Kinase/phosphatase dynamics of the Ser19 cycle in vivo not tracked"],"attribution":[{"species":"Plasmodium berghei","strain":""},{"species":"Plasmodium falciparum","strain":""}]},{"year":2023,"claim":"Whether PfMyoA is a druggable target was open; KNX-002 was shown to inhibit its ATPase and block blood-stage growth by trapping the motor in a post-rigor state detached from actin via a novel binding mode.","evidence":"In vitro ATPase assay, parasite growth assay, X-ray crystallography of the PfMyoA–inhibitor complex in P. falciparum","pmids":["37308472"],"confidence":"High","gaps":["In vivo efficacy and resistance liability not established","Selectivity over host myosins not detailed here"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"It remains unknown how the upstream PKG–CDPK1–PKA signaling, MTIP Ser108, and heavy-chain Ser19 phosphorylation events are temporally coordinated at individual invasion steps to switch the motor between force and speed modes in the living parasite.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No real-time measurement of PfMyoA phosphorylation states during invasion","Phosphatases opposing the regulatory kinases not identified","Functional role of the PfDLC1–head interaction unresolved"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":["Glideosome motor complex (PfMyoA–MTIP–GAP45–GAP50/GAP40)","PfMyoA–MTIP light-chain complex","PfMyoA–MTIP–PfELC two-light-chain motor","PfMyoA–PfAct1 actomyosin complex"],"partners":["MTIP (MLC1)","PFELC (ESSENTIAL LIGHT CHAIN)","GAP45","GAP50","GAP40","PFACT1 (ACTIN FILAMENTS)","PFDLC1 (DYNEIN LIGHT CHAIN 1)","RAB11A (VIA MTIP)","CDPK1 (REGULATORY KINASE)","PKA (REGULATORY KINASE)","PFPKG (UPSTREAM REGULATORY KINASE)"],"other_free_text":["Class XIV single-headed unconventional myosin motor.","Membrane targeting is conferred by a 15-residue C-terminal tail containing two essential arginines and residues H810/K813 that mediate the compact MTIP 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biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/30259259","citation_count":5,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["myosin A"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"28265752","id":"PMC_28265752","title":"Myosin B of Plasmodium falciparum (PfMyoB): in silico prediction of its three-dimensional structure and its possible interaction with MTIP.","date":"2017","source":"Parasitology research","url":"https://pubmed.ncbi.nlm.nih.gov/28265752","citation_count":4,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["myosin A","PfMyoA"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"31874192","id":"PMC_31874192","title":"Polarization of MTIP is a signature of gliding locomotion in Plasmodium ookinetes and sporozoites.","date":"2019","source":"Molecular and biochemical parasitology","url":"https://pubmed.ncbi.nlm.nih.gov/31874192","citation_count":3,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["MyoA","myosin A"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"38832798","id":"PMC_38832798","title":"The novel Plasmodium berghei protein S14 is essential for sporozoite gliding motility and infectivity.","date":"2024","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/38832798","citation_count":3,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["MyoA","myosin A"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"30094538","id":"PMC_30094538","title":"In vitro interaction between Plasmodium falciparum myosin B (PfMyoB) and myosin A tail interacting protein (MTIP).","date":"2018","source":"Parasitology research","url":"https://pubmed.ncbi.nlm.nih.gov/30094538","citation_count":2,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["myosin A","PfMyoA"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"36250062","id":"PMC_36250062","title":"Complementary crosstalk between palmitoylation and phosphorylation events in MTIP regulates its role during Plasmodium falciparum invasion.","date":"2022","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/36250062","citation_count":1,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["myosin A"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"40316890","id":"PMC_40316890","title":"Bilaterally Substituted Terphenyl Molecules Efficiently Inhibit the Interaction between a Protein and a Fully Buried α-Helix in the Malaria Parasite Motor System.","date":"2025","source":"Journal of the American Chemical Society","url":"https://pubmed.ncbi.nlm.nih.gov/40316890","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["MyoA","myosin A"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"12404924","id":"PMC_12404924","title":"[Preparation of DNA libraries of Plasmodium falciparum for searching calmodulin binding protein genes, GOGAT and Pfmyo A].","date":"2002","source":"Biomedica : revista del Instituto Nacional de Salud","url":"https://pubmed.ncbi.nlm.nih.gov/12404924","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["myosin A"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":27311,"output_tokens":7098,"usd":0.094201,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":14496,"output_tokens":6990,"usd":0.123615,"stage2_stop_reason":"end_turn"},"total_usd":0.0,"stage1_batch_id":"msgbatch_01FCDwJBogPrvFL5RpW1bgoz","stage2_batch_id":"msgbatch_017MJf5R7pwT6SSC5ZnYgqis","note":"batch pricing = 50% of standard","skipped":true},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"PfMyoA (Pfmyo-A / PF3D7_1342600) is synthesized in mature schizonts, present in merozoites, vanishes after erythrocyte entry, is largely associated with the particulate/membrane fraction (not solubilized by agents that dissociate actomyosin or by non-ionic detergent), and localizes by immunofluorescence and immuno-gold EM to the periphery of merozoites/schizonts, concentrated under the plasma membrane adjacent to the outer IMC membrane, with enrichment around the apical prominence.\",\n      \"method\": \"Immunoblot (stage-specificity), subcellular fractionation, immunofluorescence, immuno-gold electron microscopy\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (fractionation, IFA, immuno-EM) in a single focused study on this protein\",\n      \"pmids\": [\"9625746\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The 15 amino-acid C-terminal tail domain of PfMyoA (class XIV myosin) is the determinant for peripheral/plasma-membrane localization; truncation abolishes this localization and tight membrane association. Two essential arginine residues in the C-terminal tail are required for plasma-membrane localization, as shown by site-directed mutagenesis. The tail domain is sufficient to confer membrane localization when fused to GFP, and localization is independent of an intact F-actin cytoskeleton.\",\n      \"method\": \"Truncation analysis, site-directed mutagenesis, GFP fusion constructs, subcellular fractionation, immunofluorescence (results primarily demonstrated in TgM-A but the PfM-A sequence was completed and the dibasic motif identified across the class)\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution with mutagenesis in a single study; primary experimental work performed in Toxoplasma TgM-A but PfM-A sequence and motif explicitly characterized; attributing PfMyoA-specific sequence findings only\",\n      \"pmids\": [\"10749937\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The 15 amino-acid C-terminal tail domain of PfMyoA specifically interacts with MTIP (myosin A tail domain-interacting protein), as shown by yeast two-hybrid with deletion analysis; the neck domain does not mediate this interaction. In Plasmodium sporozoites, MyoA co-localizes with MTIP at the inner membrane complex (IMC), supporting a model where the tail-anchored MyoA moves actin filaments linked to TRAP-family proteins.\",\n      \"method\": \"Yeast two-hybrid screen with deletion analysis, immunofluorescence co-localization in sporozoites\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid with systematic deletion analysis plus in-parasite co-localization, single lab\",\n      \"pmids\": [\"12456714\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"MTIP is expressed in P. falciparum merozoites, localizes to the cell periphery, and forms a stable complex with PfMyoA (Kd ~235 nM). Calcium does not modulate this binding affinity. When the MTIP–MyoA complex is immobilized via anti-MTIP antibodies, PfMyoA drives actin filament movement at 3.51 µm/s, comparable to fast muscle myosins. A peptide derived from the MyoA C-terminal tail (C-MyoA) disrupts the MTIP–MyoA interaction in parasite lysates.\",\n      \"method\": \"Co-immunoprecipitation, surface plasmon resonance (Kd measurement), in vitro actin gliding motility assay, peptide competition assay\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro motility reconstitution, quantitative binding measurement, and peptide disruption assay in a single focused study\",\n      \"pmids\": [\"16337961\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Homologues of the glideosome motor complex proteins (including GAP45/GAP50/GAP40) are present in P. falciparum merozoites and appear to function in erythrocyte invasion, indicating the same MyoA-based motor complex operates across multiple Plasmodium life-cycle stages.\",\n      \"method\": \"Immunofluorescence, immunoblot, comparative genomics\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct protein detection and localization across stages; mechanistic inference about PfMyoA motor function supported by multiple methods\",\n      \"pmids\": [\"16321976\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"PfMyoA forms a stable complex with PfMTIP, PfGAP45, and PfGAP50 (the glideosome) in late schizonts and merozoites. PfMyoA interacts with PfMTIP through conserved mechanisms described in other eukaryotes. The glideosome complex is detected by co-immunoprecipitation from parasite lysates.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence, immunoblot\",\n      \"journal\": \"Molecular and biochemical parasitology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP of glideosome complex components, single lab\",\n      \"pmids\": [\"16513191\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Crystal structure of Plasmodium MTIP in complex with the PfMyoA tail helix reveals that MTIP undergoes major conformational changes in its C-terminal domain upon binding, creating hydrophobic pockets that receive key hydrophobic side chains of the MyoA tail helix. Three different MTIP conformations were observed in one crystal. The MyoA helix peptide alone can block parasite growth.\",\n      \"method\": \"X-ray crystallography, parasite growth inhibition assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution crystal structure with functional (growth inhibition) validation in one study\",\n      \"pmids\": [\"16547135\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"At neutral pH, the MTIP–PfMyoA complex adopts a compact conformation in which both MTIP domains (D2 and D3) completely surround the MyoA tail helix. Crystallographic and mutagenesis studies show that MyoA residues H810 (unprotonated) and K813 are essential for formation of the compact complex; K813 contacts MTIP with every side-chain atom.\",\n      \"method\": \"X-ray crystallography, site-directed mutagenesis\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure combined with mutagenesis of specific residues to validate interactions\",\n      \"pmids\": [\"17628590\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"PfCDPK1 phosphorylates MTIP (at Ser47 as the primary site) and GAP45 in vitro. Both proteins are phosphorylated in schizonts. CDPK1 localizes to the periphery of P. falciparum merozoites, suitably positioned to act on motor complex components at the IMC. Kinase inhibitor K252a inhibits both CDPK1 activity and host-cell invasion.\",\n      \"method\": \"In vitro kinase assay, mass spectrometry identification of phosphosites, indirect immunofluorescence, chemical inhibition assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro kinase assay with site identification by MS, localization, and functional inhibition; multiple orthogonal methods in one study\",\n      \"pmids\": [\"18768477\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Rab11A associates with MTIP (MLC1) and is required for IMC maturation during daughter cell formation. Inducible expression of a MyoA tail-only mutant phenocopies Rab11A ablation, causing an incompletely formed IMC and a block at late cell division, indicating that the MyoA tail (and by extension PfMyoA) is required for completion of cytokinesis/IMC assembly in addition to invasion.\",\n      \"method\": \"Co-immunoprecipitation (Rab11A–MTIP), inducible dominant-negative expression, immunofluorescence\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic dominant-negative with phenotypic readout plus co-IP; single lab\",\n      \"pmids\": [\"19165333\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Solution NMR reveals the key determinants of binding at the MTIP/PfMyoA interface; MTIP is highly dynamic and unstable in the absence of the MyoA tail partner. NMR provides the first structural characterization of the complex in solution.\",\n      \"method\": \"Protein NMR (solution structure/dynamics)\",\n      \"journal\": \"Molecular bioSystems\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — NMR structural study on the complex, single lab, no mutagenesis validation reported in abstract\",\n      \"pmids\": [\"20174678\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"P. falciparum Dynein Light Chain 1 (PfDLC1) binds PfMyoA through the SDIE and/or EEMKT motifs located in the upper 50-kDa segment of the PfMyoA head domain, as shown by interaction studies and co-immunoprecipitation. PfDLC1 co-localizes with PfMyoA in blood-stage parasites.\",\n      \"method\": \"Co-immunoprecipitation, mapping of interacting domains, immunofluorescence co-localization\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — domain-mapping interaction studies and co-IP in parasite lysates; functional consequence of PfDLC1–PfMyoA interaction not fully resolved\",\n      \"pmids\": [\"20421304\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Stage-specific depletion of PbMyoA in P. berghei ookinetes (via AMA1 promoter swap) completely abolishes ookinete gliding motility and results in a complete block of life-cycle progression in Anopheles mosquitoes, establishing an essential role for MyoA in ookinete motility.\",\n      \"method\": \"Promoter-swap conditional knockdown, gliding motility assay, mosquito transmission assay\",\n      \"journal\": \"Cellular microbiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic stage-specific depletion with quantitative motility and transmission phenotype; well-controlled conditional approach\",\n      \"pmids\": [\"21899701\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"MTIP Ser-107 and/or Ser-108 constitute a phosphorylation hotspot at the MTIP–MyoA interaction interface. Phosphomimetic mutations S108E (and to a lesser extent S107E) break the tight clamp of MTIP around the MyoA tail, as demonstrated by X-ray crystallography, NMR relaxation experiments, and biophysical binding measurements. This is consistent with reduced interaction between recombinant MTIP phosphomimetics and native PfMyoA from parasite lysates, suggesting that phosphorylation of MTIP loosens its grip on PfMyoA.\",\n      \"method\": \"X-ray crystallography, NMR relaxation, biophysical binding assays, pull-down with parasite lysates\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure + NMR + biophysical measurements + parasite-lysate validation; multiple orthogonal methods in one study\",\n      \"pmids\": [\"22932904\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"PfMyoA, GAP45, and CDPK1 are substrates of cAMP-dependent protein kinase A (PKA) in P. falciparum schizonts, as confirmed by in vitro kinase assay. This implicates cAMP/PKA signaling as an additional regulator of the glideosome motor complex alongside CDPK1.\",\n      \"method\": \"Quantitative phosphoproteomics, in vitro kinase assay\",\n      \"journal\": \"Journal of proteome research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinase assay verifying phosphoproteomics finding; single lab but two orthogonal methods\",\n      \"pmids\": [\"23025827\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PfPKG phosphorylates components of the actomyosin complex (including PfMyoA as part of the glideosome), as identified by quantitative global phosphoproteomics with chemical/genetic tools. PfPKG activity is required for parasite invasion, and PfCDPK1 is itself phosphorylated by PfPKG, placing PfPKG upstream of CDPK1 in the signaling cascade that controls the motor complex.\",\n      \"method\": \"Quantitative phosphoproteomics, chemical inhibition, conditional genetic tools\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — global phosphoproteomics with chemical/genetic validation; PfMyoA phosphorylation identified as part of a broader screen, single lab\",\n      \"pmids\": [\"26149123\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"An essential light chain (ELC/PfELC) was identified as a second light chain of PfMyoA, co-purifying with PfMyoA isolated from parasite lysates. PfELC binds the MyoA neck/IQ region adjacent to the MTIP-binding site, and its binding requires MTIP to be already bound to the heavy chain. The presence of both light chains (MTIP and ELC) together enhances PfMyoA-dependent actin filament velocity in motility assays. PfMyoA with both light chains moves PfAct1 filaments at the same speed as skeletal muscle actin. Duty ratio estimates suggest ~9 motors can power actin movement at maximal speed.\",\n      \"method\": \"Baculovirus/Sf9 recombinant protein expression, in vitro actin motility assay, mass spectrometry of parasite-derived complex, light-chain binding hierarchy experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — full reconstitution of glideosome core with in vitro motility assays, MS identification of ELC from native parasite, hierarchical binding assays; multiple orthogonal methods\",\n      \"pmids\": [\"28978649\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Throughout the P. berghei life cycle, MyoA localizes to the parasite periphery in extracellular ookinetes, sporozoites, and merozoites. In sexual stages, MyoA synthesis occurs only in the developing ookinete protuberance, not in zygotes. In asexual blood stages, MyoA is synthesized in mature schizonts and persists at the merozoite periphery through egress and invasion. The glideosome complex includes GAP40, an additional essential light chain (ELC) binding the MyoA neck, and other candidate components. Co-expression of MyoA with both light chains enhances actin motility.\",\n      \"method\": \"Immunofluorescence (life-cycle staging), in vitro motility assay, co-expression and functional assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic life-cycle localization plus in vitro motility reconstitution with light chain variants; multiple orthogonal methods, validated in P. berghei\",\n      \"pmids\": [\"28893907\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PfMyoA is critical for red blood cell invasion by P. falciparum. Using X-ray crystallography (three structures in different states), kinetic assays, and in vitro motility assays, PfMyoA was shown to operate via non-canonical interactions. Heavy chain phosphorylation at Ser19 tunes motor properties: unphosphorylated PfMyoA exhibits enhanced ensemble force generation at reduced speed, whereas phosphorylation increases speed. This regulated phosphorylation may optimize PfMyoA for force generation during invasion or fast motility during dissemination.\",\n      \"method\": \"X-ray crystallography (three structural states), steady-state and transient kinetics, in vitro actin motility assay, conditional mutagenesis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — three crystal structures plus kinetics plus motility assays; multiple orthogonal high-tier methods in one study\",\n      \"pmids\": [\"31337750\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Full-length PfMyoA structures in two states of the motor cycle reveal novel interactions essential for motor priming and show the mode of recognition of two light chains (PfELC and MTIP) by two degenerate IQ motifs. Kinetic and motility assays with PfMyoA variants and molecular dynamics demonstrate how specific priming and atypical sequence adaptations tune mechano-chemical properties. PfELC has an essential role in malaria pathogenesis.\",\n      \"method\": \"X-ray crystallography (full-length, two motor states), kinetics, in vitro motility assays, molecular dynamics simulations\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — full-length crystal structures in multiple states combined with kinetic and motility validation; multiple orthogonal high-tier methods\",\n      \"pmids\": [\"33046215\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Conditional mutagenesis targeting a key PfMyoA phospho-regulation site (Ser19), absence of the PfELC, or complete motor absence each cause distinct stages of incomplete RBC invasion, defining three energetic barriers: RBC deformation (pre-entry), mid-invasion initiation, and completion of internalization. Each barrier requires active PfMyoA motor function.\",\n      \"method\": \"Conditional mutagenesis, live video microscopy, invasion assay\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional genetics with quantitative live-imaging of invasion stages; three distinct mutant series with graded mechanistic phenotypes\",\n      \"pmids\": [\"33104759\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Cryo-EM structure of the P. falciparum actomyosin complex at the end of the powerstroke (rigor state) shows that the PfMyoA footprint on PfAct1 filaments is conserved with respect to higher eukaryotes despite important sequence variability. The interface contains a conserved core common to all actomyosin complexes and an ancillary interface defining spatial positioning of the motor on actin.\",\n      \"method\": \"Electron cryomicroscopy (cryo-EM), atomic model building\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — atomic-resolution cryo-EM structure of the native actomyosin complex in a defined functional state\",\n      \"pmids\": [\"33767187\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Phosphorylation of PbMyoA Ser19 increases ookinete gliding motility but does not affect sporozoite speed under standard 2D conditions. S19A mutants show defects in mosquito salivary gland entry. In 3D environments, both S19A and E6R mutations slow ookinetes and salivary gland sporozoites and lower force generation. These data establish that the Ser19 phosphorylation cycle of MyoA influences parasite migration and force generation and is critical for transmission.\",\n      \"method\": \"Phospho-mutant parasite generation (S19A, S19D, E6R), 2D and 3D gliding motility assays, mosquito transmission assay, force measurement\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic phospho-mutants with quantitative motility and force measurements across multiple contexts and life stages; replicated across conditions\",\n      \"pmids\": [\"35506479\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"High-resolution cryo-EM structure of the P. falciparum actomyosin complex confirms the PfAct1:PfMyoA interface at atomic detail and, at lower resolution, resolves the PfMyoA light-chain binding region accommodating both PfELC and PfMTIP.\",\n      \"method\": \"Electron cryomicroscopy (cryo-EM), high-resolution structure determination\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution cryo-EM with atomic-detail interface; independent replication of actomyosin complex structure\",\n      \"pmids\": [\"35377914\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Small molecule KNX-002 inhibits PfMyoA ATPase activity in vitro and blocks asexual blood stage merozoite growth. X-ray crystallography shows KNX-002 binds PfMyoA using a previously undescribed binding mode, sequestering it in a post-rigor state detached from actin, preventing efficient ATP hydrolysis and lever-arm priming.\",\n      \"method\": \"In vitro ATPase assay, parasite growth assay, X-ray crystallography of PfMyoA–inhibitor complex\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure of motor–inhibitor complex combined with biochemical ATPase assay and parasite growth inhibition; three orthogonal methods\",\n      \"pmids\": [\"37308472\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"PfMyoA (PF3D7_1342600) is a class XIV unconventional single-headed myosin motor whose C-terminal tail helix binds the light chain MTIP (with Kd ~235 nM) through large conformational changes in MTIP, while a second light chain PfELC binds the adjacent IQ motif and together the two light chains act as a lever arm to enhance motor speed and force generation; the motor drives actin filament movement at ~3.5 µm/s, is anchored to the inner membrane complex via MTIP and glideosome-associated proteins (GAP45, GAP50, GAP40), and its activity is regulated by phosphorylation of its heavy chain Ser19 (balancing force versus speed) by CDPK1 and PKA downstream of PKG signaling, with phosphorylation of MTIP Ser108 loosening the MTIP–MyoA clamp; the motor is essential for gliding motility, erythrocyte invasion, ookinete motility, and mosquito transmission, with its absence or impairment defining distinct mechanical barriers to RBC invasion.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PfMyoA (PF3D7_1342600) is a class XIV unconventional single-headed myosin motor that powers the actin-based gliding machinery underlying Plasmodium erythrocyte invasion and life-cycle motility [#0, #18]. The protein is synthesized in mature schizonts and merozoites and anchored to the parasite periphery beneath the plasma membrane adjacent to the inner membrane complex, a localization determined by its short 15-residue C-terminal tail — including two essential arginines — that mediates membrane attachment independently of the F-actin cytoskeleton [#0, #1]. This same tail helix binds the light chain MTIP (Kd ~235 nM), and reconstitution of the MTIP–PfMyoA complex drives actin filament movement at ~3.5 µm/s, comparable to fast muscle myosins [#3]. A second light chain, PfELC, binds an adjacent degenerate IQ motif contingent on prior MTIP binding, and together the two light chains act as a lever arm that enhances motor velocity to match skeletal-muscle-actin gliding speeds [#16, #19]. Crystallographic and cryo-EM work has resolved the MTIP–tail interface, the compact clamp conformation, the full-length motor in distinct catalytic states, and the conserved actomyosin footprint on PfAct1 [#6, #7, #19, #21]. Motor output is tuned by phosphorylation of heavy-chain Ser19 — the unphosphorylated form favors ensemble force generation at reduced speed while phosphorylation increases speed — and by phosphorylation of MTIP Ser107/Ser108, which loosens the MTIP grip on the tail; upstream, PfPKG, CDPK1, and PKA converge on the motor complex [#8, #13, #14, #15, #18]. Genetic ablation and phospho-mutant studies establish that active PfMyoA is essential for gliding, ookinete motility and mosquito transmission, and defines distinct mechanical barriers to RBC invasion, and the ATPase inhibitor KNX-002 blocks blood-stage growth by trapping the motor detached from actin [#12, #20, #22, #24].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Establishing when and where PfMyoA acts required defining its stage expression and subcellular position; this study showed it is a merozoite/schizont peripheral protein tightly associated with the membrane at the IMC.\",\n      \"evidence\": \"Immunoblot staging, subcellular fractionation, IFA and immuno-gold EM in P. falciparum\",\n      \"pmids\": [\"9625746\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not identify the molecular anchor mediating membrane association\", \"No direct functional readout of motor activity\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"The determinant of PfMyoA's membrane localization was unknown; mutagenesis identified the 15-residue C-terminal tail and two essential arginines as necessary and sufficient for peripheral targeting.\",\n      \"evidence\": \"Truncation, site-directed mutagenesis and GFP fusions (tail motif characterized for PfM-A; primary constructs in Toxoplasma)\",\n      \"pmids\": [\"10749937\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding partner engaged by the tail not identified here\", \"Core experimental work performed in the Toxoplasma ortholog\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"What the PfMyoA tail binds was unresolved; a yeast two-hybrid screen identified MTIP as the specific tail-interacting partner at the IMC, linking the motor to the membrane skeleton.\",\n      \"evidence\": \"Yeast two-hybrid with deletion analysis and sporozoite co-localization\",\n      \"pmids\": [\"12456714\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Binding affinity and stoichiometry not quantified\", \"Motor activity of the complex not tested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Whether the MTIP–PfMyoA complex is a functional motor was untested; quantitative binding and in vitro motility assays showed a stable complex (Kd ~235 nM) that drives fast actin gliding at 3.5 µm/s.\",\n      \"evidence\": \"Co-IP, surface plasmon resonance, in vitro actin gliding, peptide competition in P. falciparum\",\n      \"pmids\": [\"16337961\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Second light chain not yet identified\", \"Regulation of motor speed not addressed\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"The broader motor assembly and the atomic basis of tail recognition were undefined; co-IP placed PfMyoA in a stable glideosome with MTIP/GAP45/GAP50 and crystallography revealed MTIP undergoes large conformational changes to grip the tail helix.\",\n      \"evidence\": \"Co-IP/IFA of glideosome components and X-ray crystallography with growth-inhibition assay in P. falciparum\",\n      \"pmids\": [\"16513191\", \"16547135\", \"16321976\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether membrane anchoring is via GAP proteins not resolved\", \"Functional consequence of each GAP subunit for motor output untested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"The conformational details of the clamped complex were unknown; crystallography plus mutagenesis showed both MTIP domains fully surround the tail at neutral pH, with residues H810 and K813 essential for the compact complex.\",\n      \"evidence\": \"X-ray crystallography and site-directed mutagenesis in P. falciparum\",\n      \"pmids\": [\"17628590\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How the clamp is released or regulated not addressed\", \"In-parasite consequence of clamp mutations not tested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"How the motor complex is regulated was unclear; CDPK1 was shown to phosphorylate MTIP (Ser47) and GAP45, localize to the merozoite periphery, and its inhibition blocked invasion, implicating kinase control of the motor.\",\n      \"evidence\": \"In vitro kinase assay with MS phosphosite mapping, IFA and chemical inhibition in P. falciparum\",\n      \"pmids\": [\"18768477\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct effect of MTIP Ser47 phosphorylation on motor activity not measured\", \"Whether PfMyoA heavy chain is a CDPK1 substrate not established here\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Whether PfMyoA function extends beyond invasion was unknown; a MyoA tail-only dominant negative phenocopied Rab11A loss, revealing a requirement for the motor in IMC assembly and cytokinesis.\",\n      \"evidence\": \"Rab11A–MTIP co-IP, inducible dominant-negative expression, IFA in P. falciparum\",\n      \"pmids\": [\"19165333\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Dominant-negative may titrate MTIP rather than reflect endogenous motor role\", \"Mechanism linking motor to IMC maturation not defined\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"The solution behavior of the interface and additional head-domain partners were undefined; NMR showed MTIP is dynamic and unstable without the tail, and a separate study mapped PfDLC1 binding to head-domain motifs.\",\n      \"evidence\": \"Solution NMR of the complex; domain-mapping/co-IP and co-localization for PfDLC1 in P. falciparum\",\n      \"pmids\": [\"20174678\", \"20421304\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of the PfDLC1–PfMyoA interaction unresolved\", \"NMR study lacked mutagenesis validation\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Whether MyoA is genetically essential for motility in vivo was untested; stage-specific depletion of PbMyoA abolished ookinete gliding and blocked mosquito transmission.\",\n      \"evidence\": \"Promoter-swap conditional knockdown with gliding and transmission assays in P. berghei\",\n      \"pmids\": [\"21899701\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of motility loss not dissected\", \"Does not address asexual blood-stage essentiality\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"The mechanistic role of interface phosphorylation was unknown; structural and biophysical work showed phosphomimetic MTIP Ser108/Ser107 breaks the tight clamp around the tail, and PKA was identified as an additional kinase acting on PfMyoA and GAP45.\",\n      \"evidence\": \"Crystallography, NMR relaxation, biophysical binding, parasite-lysate pull-downs; phosphoproteomics with in vitro kinase assay in P. falciparum\",\n      \"pmids\": [\"22932904\", \"23025827\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In-parasite consequence of MTIP dephosphorylation/phosphorylation on invasion not directly measured\", \"Kinase responsible for MTIP Ser108 in vivo not pinned down\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"The signaling hierarchy controlling the motor was incomplete; phosphoproteomics placed PfPKG upstream of CDPK1 and identified actomyosin components including PfMyoA as targets of the PKG-driven cascade required for invasion.\",\n      \"evidence\": \"Quantitative phosphoproteomics with chemical and conditional-genetic tools in P. falciparum\",\n      \"pmids\": [\"26149123\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct PfMyoA phosphosites attributable to PKG not individually validated\", \"Motor activity consequence not measured\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"The full light-chain composition and its effect on motor output were unresolved; PfELC was identified as a second light chain that binds the neck/IQ region only after MTIP, and together the two light chains enhance actin velocity to skeletal-actin levels.\",\n      \"evidence\": \"Recombinant reconstitution, in vitro motility, MS of native complex, hierarchical binding assays in P. falciparum; life-cycle localization and motility in P. berghei\",\n      \"pmids\": [\"28978649\", \"28893907\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the two-light-chain lever arm not yet resolved at this stage\", \"In-parasite requirement for PfELC not yet tested\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}, {\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"How PfMyoA's atypical sequence and Ser19 phosphorylation tune its mechanics was unknown; three crystal structures plus kinetics showed non-canonical interactions and that Ser19 phosphorylation trades force for speed.\",\n      \"evidence\": \"X-ray crystallography (three states), steady-state/transient kinetics, in vitro motility, conditional mutagenesis in P. falciparum\",\n      \"pmids\": [\"31337750\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full-length motor with both light chains not yet structurally resolved here\", \"In vivo kinase controlling Ser19 not defined\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"The structural mode of light-chain recognition and the graded functional roles of motor regulation in invasion were unresolved; full-length structures revealed two degenerate IQ motifs engaging PfELC and MTIP, and conditional mutants defined three distinct energetic barriers to RBC invasion requiring active motor.\",\n      \"evidence\": \"Full-length crystallography in two motor states with MD and kinetics; conditional mutagenesis with live invasion imaging in P. falciparum\",\n      \"pmids\": [\"33046215\", \"33104759\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise in vivo phosphorylation state during each invasion step not measured\", \"How force is transmitted to the RBC membrane not structurally captured\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"The atomic interface between PfMyoA and its actin track was undefined; cryo-EM of the rigor-state actomyosin complex showed a conserved core interface plus an ancillary interface positioning the motor on PfAct1.\",\n      \"evidence\": \"Cryo-EM and atomic model building of the native actomyosin complex in P. falciparum\",\n      \"pmids\": [\"33767187\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Only the rigor state captured; intermediate powerstroke states not resolved\", \"Light-chain region not resolved in this structure\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Whether Ser19 phosphorylation matters for whole-organism motility and transmission was untested; phospho-mutant parasites showed Ser19 phosphorylation controls ookinete gliding, force generation in 3D, and salivary-gland invasion, and higher-resolution cryo-EM resolved both light chains at the neck.\",\n      \"evidence\": \"Phospho-mutant (S19A/S19D/E6R) parasites with 2D/3D motility, force and transmission assays in P. berghei; high-resolution cryo-EM of the actomyosin complex in P. falciparum\",\n      \"pmids\": [\"35506479\", \"35377914\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Sporozoite speed under standard 2D conditions unaffected, leaving stage-specific requirements incompletely explained\", \"Kinase/phosphatase dynamics of the Ser19 cycle in vivo not tracked\"],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}, {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Whether PfMyoA is a druggable target was open; KNX-002 was shown to inhibit its ATPase and block blood-stage growth by trapping the motor in a post-rigor state detached from actin via a novel binding mode.\",\n      \"evidence\": \"In vitro ATPase assay, parasite growth assay, X-ray crystallography of the PfMyoA–inhibitor complex in P. falciparum\",\n      \"pmids\": [\"37308472\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo efficacy and resistance liability not established\", \"Selectivity over host myosins not detailed here\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how the upstream PKG–CDPK1–PKA signaling, MTIP Ser108, and heavy-chain Ser19 phosphorylation events are temporally coordinated at individual invasion steps to switch the motor between force and speed modes in the living parasite.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No real-time measurement of PfMyoA phosphorylation states during invasion\", \"Phosphatases opposing the regulatory kinases not identified\", \"Functional role of the PfDLC1–head interaction unresolved\"],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0000146\", \"supporting_discovery_ids\": [3, 16, 17, 18, 19, 24]},\n      {\"term_id\": \"GO:0016887\", \"supporting_discovery_ids\": [24]},\n      {\"term_id\": \"GO:0051015\", \"supporting_discovery_ids\": [3, 16, 21, 23]},\n      {\"term_id\": \"GO:0032036\", \"supporting_discovery_ids\": [2, 3, 16, 19]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0020039\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"GO:0033112\", \"supporting_discovery_ids\": [5, 6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0071973\", \"supporting_discovery_ids\": [12, 17, 22]},\n      {\"term_id\": \"GO:0006909\", \"supporting_discovery_ids\": [18, 20]},\n      {\"term_id\": \"GO:0007018\", \"supporting_discovery_ids\": [3, 21]},\n      {\"term_id\": \"GO:0000281\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"complexes\": [\n      \"Glideosome motor complex (PfMyoA–MTIP–GAP45–GAP50/GAP40)\",\n      \"PfMyoA–MTIP light-chain complex\",\n      \"PfMyoA–MTIP–PfELC two-light-chain motor\",\n      \"PfMyoA–PfAct1 actomyosin complex\"\n    ],\n    \"partners\": [\n      \"MTIP (MLC1)\",\n      \"PfELC (essential light chain)\",\n      \"GAP45\",\n      \"GAP50\",\n      \"GAP40\",\n      \"PfAct1 (actin filaments)\",\n      \"PfDLC1 (dynein light chain 1)\",\n      \"Rab11A (via MTIP)\",\n      \"CDPK1 (regulatory kinase)\",\n      \"PKA (regulatory kinase)\",\n      \"PfPKG (upstream regulatory kinase)\"\n    ],\n    \"other_free_text\": [\n      \"Class XIV single-headed unconventional myosin motor.\",\n      \"Membrane targeting is conferred by a 15-residue C-terminal tail containing two essential arginines and residues H810/K813 that mediate the compact MTIP clamp.\",\n      \"Motor mechanics are tuned by heavy-chain Ser19 phosphorylation (force vs speed) and by MTIP Ser107/Ser108 phosphorylation that loosens the tail clamp.\",\n      \"Two degenerate IQ motifs engage MTIP then PfELC (hierarchical binding) to form a lever arm enhancing actin gliding velocity.\",\n      \"KNX-002 is a small-molecule ATPase inhibitor that sequesters PfMyoA in a post-rigor, actin-detached state and blocks blood-stage growth.\",\n      \"Findings span P. falciparum (blood-stage invasion, structure, biochemistry) and P. berghei (ookinete/sporozoite motility and transmission).\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_1342600","name":null,"product":"myosin A","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_1355700","name":null,"product":"myosin A","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1258800","name":null,"product":"myosin A, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"MyoA","evaluation":null}