Affinage · Plasmodium

LISP2

PF3D7_0405300 · liver specific protein 2, putative

Annotated
2026-09-07
14 papers in source corpus 9 papers cited in narrative 9 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

LISP2 (PF3D7_0405300) is a liver-stage-specific protein whose expression marks the transition of intrahepatic Plasmodium parasites into active schizogony and whose function is required for completion of liver-stage development (PMID:23216750, PMID:31094679). First characterized in P. berghei, LISP2 is expressed from ~24 h post-infection, localizes to the parasitophorous vacuole, and in rodent parasites is exported to the cytoplasm and nucleus of the host hepatocyte; its genetic disruption arrests the majority of parasites during merozoite formation (PMID:23216750). Across relapsing-malaria species (P. cynomolgi, P. vivax), LISP2 is expressed in developing schizonts but not in dormant hypnozoites, making it a molecular and functional marker that discriminates active liver-stage development from dormancy and correlating its expression with drug-sensitive schizogony (PMID:31094679). Genetic loss-of-function is consistent across Plasmodium species, with residual breakthrough after single deletion in P. berghei that becomes complete attenuation when combined with uis3 deletion, and synthetic lethality with PlasMei2 deletion in P. yoelii, placing LISP2 in a late liver-stage developmental pathway that is partially redundant with these factors (PMID:29440367, PMID:27241521). In P. falciparum, LISP2 carries a classical bipartite nuclear localization signal in its C-terminus that is necessary and sufficient to direct nuclear import into hepatocytes via the importin-α/β pathway, while the protein lacks any export signal (PMID:39601512); notably, in P. falciparum humanized-mouse liver stages LISP2 remains at the parasite periphery and is not exported beyond the parasitophorous vacuole membrane, and its accumulation depends on the PTEX translocon components EXP2 and PTEX150 (PMID:38968107, PMID:36445080). The LISP2 promoter itself is a functional, stage-specific regulatory element sufficient to drive schizont-restricted reporter expression in vivo (PMID:25874388, PMID:32267675). Beyond these findings, no biochemical activity or direct molecular partners for the LISP2 protein have been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2012 High

    Established that LISP2 is a liver-stage-expressed protein exported from the vacuole to the host hepatocyte and required for intrahepatic development, defining its cellular role in parasite-host interaction.

    Evidence Anti-LISP2 immunofluorescence plus gene knockout with liver-stage phenotyping in P. berghei

    PMID:23216750

    Open questions at the time
    • No molecular mechanism for the arrest during merozoite formation
    • Host-cell targets or biochemical activity of exported LISP2 unknown
  2. 2015 Medium

    Dissected the LISP2 promoter to show it is an autonomous stage-specific regulatory element, explaining how LISP2 expression is restricted to the liver stage.

    Evidence Dual-luminescence reporter assays with promoter substitution/deletion constructs in P. berghei

    PMID:25874388

    Open questions at the time
    • Trans-acting factors binding the identified promoter elements not identified
    • Does not connect promoter activity to protein function
  3. 2016 Medium

    Positioned LISP2 in a partially redundant late liver-stage pathway by showing single deletion allows breakthrough while combination with uis3 deletion gives complete attenuation.

    Evidence Single and double gene knockout with in vivo sporozoite challenge in P. berghei ANKA

    PMID:27241521

    Open questions at the time
    • Molecular basis of redundancy with UIS3 not defined
    • Whether LISP2 and UIS3 act in the same biochemical process unclear
  4. 2018 Medium

    Demonstrated genetic synthetic lethality between LISP2 and PlasMei2, establishing that LISP2 function overlaps with PlasMei2 in enabling late liver-stage development.

    Evidence Double gene knockout with in vivo mouse infection and blood-stage breakthrough assessment in P. yoelii

    PMID:29440367

    Open questions at the time
    • Mechanistic link between LISP2 and PlasMei2 not defined
    • Single lab; epistasis not extended to other species
  5. 2019 High

    Defined LISP2 as a marker discriminating active schizogony from dormant hypnozoites, functionally linking its expression to the onset of development and drug sensitivity.

    Evidence Immunofluorescence in P. cynomolgi (in vitro) and P. vivax (in vivo) with drug-sensitivity correlation

    PMID:31094679

    Open questions at the time
    • Regulatory switch controlling LISP2 onset at schizogony not identified
    • Whether LISP2 is causal for, or merely coincident with, the dormancy exit unknown
  6. 2020 Medium

    Exploited the LISP2 promoter as a schizont-specific driver, confirming it is active in developing but not dormant liver stages and providing a bioluminescent readout for schizogony.

    Evidence Transgenic P. cynomolgi expressing luciferase under the lisp2 promoter with bioluminescence assays

    PMID:32267675

    Open questions at the time
    • Applied use rather than new mechanistic insight into LISP2 protein
    • Promoter regulation in P. cynomolgi not dissected at element level
  7. 2022 Medium

    Placed LISP2 expression downstream of PTEX pore activity by showing EXP2 knockdown abolishes LISP2 accumulation during intrahepatic development.

    Evidence glmS conditional EXP2 knockdown with LISP2 immunofluorescence and nanoluciferase developmental readout in P. berghei

    PMID:36445080

    Open questions at the time
    • Whether EXP2 acts on LISP2 directly or via general developmental arrest unresolved
    • Does not distinguish effects on transcription vs trafficking/stability
  8. 2024 High

    Resolved the mechanism of LISP2 nuclear targeting by identifying a C-terminal bipartite NLS necessary and sufficient for importin-α/β-mediated import into hepatocytes.

    Evidence NLS-fusion constructs, site-directed mutagenesis, and importin inhibitor coexpression in HepG2 cells with fluorescence microscopy in P. falciparum

    PMID:39601512

    Open questions at the time
    • Nuclear function of imported LISP2 not established
    • NLS shown unique to P. falciparum/P. reichenowi, so import route may differ in rodent species
  9. 2024 Medium

    Showed that P. falciparum LISP2 stays at the parasite periphery (not exported beyond the PVM) and that its expression depends on PTEX components PTEX150 and EXP2, refining LISP2 trafficking and its dependence on the translocon.

    Evidence Flp/FRT conditional excision of ptex150 and exp2 with LISP2 immunofluorescence in humanized-mouse P. falciparum liver stages

    PMID:38968107

    Open questions at the time
    • Peripheral localization in P. falciparum contrasts with host-cytoplasm/nucleus export reported in P. berghei; species difference unresolved
    • Whether PTEX dependence reflects direct export of LISP2 or indirect developmental effect unclear

Open questions

Synthesis pass · forward-looking unresolved questions
  • The biochemical activity of the LISP2 protein and its molecular targets in the parasite or host cell remain unknown, leaving open how LISP2 drives liver-stage completion and what it does once imported into the hepatocyte nucleus.
  • No direct protein interaction partner identified
  • No enzymatic or structural characterization
  • Function of nuclear-imported LISP2 in host hepatocytes undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
EXP2 / PTEX150 (PTEX TRANSLOCON; LISP2 EXPRESSION/ACCUMULATION DEPENDS ON THEM) [#6, #8]IMPORTIN-Α/Β (MEDIATES LISP2 NUCLEAR IMPORT IN P. FALCIPARUM) [#7]PLASMEI2 (SYNTHETIC-LETHAL GENETIC INTERACTION IN P. YOELII) [#2]UIS3 (GENETIC INTERACTION; COMBINED DELETION GIVES COMPLETE ATTENUATION IN P. BERGHEI) [#3]

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2012 LISP2 (liver-specific protein 2) is expressed in Plasmodium berghei liver-stage parasites starting 24 h post-infection, localizes to the parasitophorous vacuole, and is subsequently exported to the cytoplasm and nucleus of host hepatocytes. Gene targeting (knockout) of LISP2 caused the majority of liver-stage parasites to arrest during merozoite formation, establishing a required role in parasite-host interactions during intrahepatic development. Immunofluorescence staining with anti-LISP2 antibodies; gene targeting/disruption with phenotypic analysis of liver-stage development Molecular microbiology High 23216750
2019 LISP2 is expressed in early developing liver-stage parasites (schizonts) but not in dormant hypnozoites of P. cynomolgi (in vitro) and P. vivax (in vivo), establishing LISP2 as a molecular marker that discriminates active liver-stage schizogony from dormancy. Prophylactic drugs selectively killed all LISP2-positive parasites, while LISP2-negative hypnozoites were only sensitive to tafenoquine, functionally linking LISP2 expression to the onset of schizogony. Immunofluorescence analysis of hepatocytes infected with P. cynomolgi (in vitro) and P. vivax (in vivo); drug treatment experiments correlating LISP2 status with drug sensitivity eLife High 31094679
2018 Dual deletion of LISP2 and PlasMei2 in Plasmodium yoelii produced a synthetic lethal phenotype causing complete late liver-stage arrest with no breakthrough blood-stage infection, establishing that LISP2 acts in a pathway required for late liver-stage development and that its function is partially redundant with PlasMei2 in this context. Genetic double-knockout (LISP2 and PlasMei2) in P. yoelii with assessment of liver-stage arrest and blood-stage breakthrough by in vivo infection of mice Infection and immunity Medium 29440367
2016 Single deletion of LISP2 in Plasmodium berghei ANKA caused liver-stage developmental arrest but with occasional breakthrough infections; combining LISP2 deletion with uis3 deletion produced complete attenuation, indicating LISP2 function is required for liver-stage completion and that its pathway is partially separable from that of UIS3. Single and double gene knockout in P. berghei with in vivo sporozoite challenge assays measuring breakthrough blood-stage infection Scientific reports Medium 27241521
2015 The LISP2 gene promoter region from Plasmodium berghei confers liver-stage-specific (stage-enriched) expression in vivo, as confirmed by dual-luminescence reporter assays. Substitution and deletion analyses identified specific elements within the promoter required for stage-specific activity. Dual luminescence reporter assays with promoter substitution and deletion analyses in P. berghei in vivo and in vitro PloS one Medium 25874388
2020 The LISP2 promoter (schizont-specific) was used to drive firefly luciferase expression in transgenic P. cynomolgi, enabling bioluminescence-based discrimination of liver-stage schizonts from hypnozoites. This functional use confirms that the LISP2 promoter is active specifically in developing (schizont) liver stages but not in dormant hypnozoites of P. cynomolgi. Transgenic parasite engineering with firefly luciferase under lisp2 promoter control; bioluminescence assay in 96-well and 384-well formats Analytical chemistry Medium 32267675
2022 Post-invasion knockdown of EXP2 in Plasmodium berghei largely abolished expression of the mid-to-late liver-stage marker LISP2, placing LISP2 expression downstream of EXP2/PTEX function during intrahepatic development. This establishes that LISP2 accumulation depends on intact EXP2-mediated vacuolar pore activity. glmS ribozyme-mediated conditional knockdown of EXP2 after hepatocyte invasion in P. berghei; immunofluorescence to assess LISP2 expression; nanoluciferase reporter for developmental readout mBio Medium 36445080
2024 P. falciparum LISP2 (Pf-LISP2) contains a classical bipartite nuclear localization signal (NLS) in its C-terminal region that is essential for nuclear import into HepG2 hepatocytes. Fusion of the Pf-LISP2 NLS to Pf-aldolase directed the chimera exclusively to the nucleus. Mutation of key lysine and arginine residues in the bipartite NLS abolished nuclear localization. Nuclear import required importin-α/β interaction, as coexpression with the importin-α/β inhibitor mCherry-Bimax2 blocked translocation. Pf-LISP2 lacks any nuclear export signal. Phylogenetic analysis showed this NLS is unique to P. falciparum and P. reichenowi. NLS-fusion constructs (Pf-aldolase-NLS-EGFP) expressed in HepG2 cells; site-directed mutagenesis of NLS basic residues; importin-α/β inhibitor (mCherry-Bimax2) coexpression; fluorescence microscopy; phylogenetic analysis ACS infectious diseases High 39601512
2024 P. falciparum LISP2 localizes to the periphery of P. falciparum liver stages in humanized mice but is not exported beyond the parasitophorous vacuole membrane (PVM). Disruption of PTEX members PTEX150 and EXP2 reduced LISP2 expression in P. falciparum liver stages, indicating that LISP2 expression or accumulation is dependent — directly or indirectly — on intact PTEX function. Flp/FRT conditional gene excision of ptex150 and exp2 in P. falciparum sporozoites; localization of LISP2 by immunofluorescence in humanized mice liver stages; comparison of LISP2 expression between knockout and wild-type parasites Proceedings of the National Academy of Sciences of the United States of America Medium 38968107

Source papers

Stage 0 corpus · 14 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2012 Liver-specific protein 2: a Plasmodium protein exported to the hepatocyte cytoplasm and required for merozoite formation. Molecular microbiology 68 23216750
2019 The Plasmodium liver-specific protein 2 (LISP2) is an early marker of liver stage development. eLife 46 31094679
2018 A Plasmodium Parasite with Complete Late Liver Stage Arrest Protects against Preerythrocytic and Erythrocytic Stage Infection in Mice. Infection and immunity 37 29440367
2016 Protective efficacy and safety of liver stage attenuated malaria parasites. Scientific reports 23 27241521
2014 D-Glucose concentration is the key factor facilitating liver stage maturation of Plasmodium. Parasitology international 18 24691399
2015 In silico identification of genetically attenuated vaccine candidate genes for Plasmodium liver stage. Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 16 26348884
2015 In vivo and in vitro characterization of a Plasmodium liver stage-specific promoter. PloS one 13 25874388
2020 Dual-Luciferase-Based Fast and Sensitive Detection of Malaria Hypnozoites for the Discovery of Antirelapse Compounds. Analytical chemistry 11 32267675
2022 The PTEX Pore Component EXP2 Is Important for Intrahepatic Development during the Plasmodium Liver Stage. mBio 10 36445080
2024 Flp/FRT-mediated disruption of ptex150 and exp2 in Plasmodium falciparum sporozoites inhibits liver-stage development. Proceedings of the National Academy of Sciences of the United States of America 8 38968107
2020 Definition of constitutive and stage-enriched promoters in the rodent malaria parasite, Plasmodium yoelii. Malaria journal 5 33228734
2025 Complete attenuation of Plasmodium falciparum sporozoites by atovaquone-proguanil. EMBO molecular medicine 2 41023197
2024 Mapping of Nuclear Localization Signal in Secreted Liver-Specific Protein 2 of Plasmodium falciparum. ACS infectious diseases 1 39601512
2026 Naturally acquired antibodies to Plasmodium vivax Pv_LISP-2, a potential liver stage vaccine antigen. Frontiers in immunology 0 41972120