Affinage · Plasmodium

GRASP

PF3D7_1017300 · golgi re-assembly stacking protein 1, golgi re-assembly stacking protein 2

Annotated
2026-09-08
5 papers in source corpus 5 papers cited in narrative 5 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PF3D7_1017300 (GRASP) is a Golgi re-assembly stacking protein of the malaria parasite that marks and organizes the parasite's cis-Golgi compartment across the asexual life cycle (PMID:16306223). The gene is expressed as a 70 kDa protein localizing to a single juxtanuclear Golgi compartment distinct from the ER, co-localizing with the cis-Golgi marker ERD2 and remaining insensitive to Brefeldin A (PMID:16306223). In P. falciparum, PF3D7_1017300 produces two isoforms via alternative splicing that reach the Golgi by distinct routes: GRASP1 depends on a cross-species conserved myristoylation motif for correct Golgi targeting (PMID:16306223, PMID:18522993), whereas GRASP2 uses a distinct hydrophobic, signal-anchor-like N-terminus for membrane attachment (PMID:18522993). Its cis-Golgi residency spatially separates from the trans-Golgi (Rab6-marked) face during parasite maturation, with Golgi multiplication linked to transitional-ER multiplication (PMID:18284574). Beyond its role as a Golgi organizer, the P. berghei ortholog associates with ATG8-positive autophagosomes during liver-stage development and acts as a regulator of parasite proliferation and virulence: knockout parasites are normal in mosquito and blood stages but show altered liver-stage schizogony and, following normal merozoite egress, produce higher parasitemia with delayed and reduced cerebral malaria (PMID:40143578). No enzymatic activity, direct binding partners, or structural model for PF3D7_1017300 itself have been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 5 steps
  1. 2005 High

    Establishing where GRASP resides answered whether the parasite maintains a discrete Golgi compartment and how the protein is targeted there.

    Evidence GFP-fusion live imaging with ERD2 co-localization, Brefeldin A treatment, and myristoylation-motif mutagenesis in P. falciparum transgenic parasites

    PMID:16306223

    Open questions at the time
    • Does not identify GRASP binding partners or its molecular function in Golgi stacking
    • No structural characterization of the myristoylation-dependent targeting
  2. 2008 Medium

    Reciprocal marker imaging established that the GRASP-marked cis-Golgi separates spatially from the trans-Golgi during maturation, linking Golgi biogenesis to the transitional ER.

    Evidence Double-transfectant live imaging of GRASP-GFP with Rab6-DsRed in P. falciparum

    PMID:18284574

    Open questions at the time
    • Two markers in a single lab; mechanism coupling Golgi and tER multiplication not defined
    • No functional perturbation of GRASP tested
  3. 2008 Medium

    Discovery of two splice isoforms answered how a single gene achieves Golgi association through two distinct membrane-attachment strategies.

    Evidence Splice-variant identification, GFP-fusion localization, and N-terminus deletion/mutagenesis with phylogenetic analysis in P. falciparum

    PMID:18522993

    Open questions at the time
    • Functional distinction between GRASP1 and GRASP2 roles not established
    • Whether both isoforms are simultaneously required is untested
  4. 2015 Low

    GRASP served instrumentally as a validated Golgi resident marker, reinforcing its cis-Golgi localization while not addressing its own mechanism.

    Evidence Immunofluorescence co-localization of Pfμ1-GFP with GRASP under AlF4 treatment in P. falciparum

    PMID:25573429

    Open questions at the time
    • GRASP used only as a marker; no direct mechanistic data on GRASP
    • Single indirect readout
  5. 2025 Medium

    Genetic knockout in P. berghei answered whether GRASP has a physiological role beyond Golgi structure, revealing a stage-specific function in liver-stage growth control and host virulence.

    Evidence PbGRASP knockout parasites with GRASP-autophagosome (ATG8) co-localization imaging and mouse infection models scoring parasitemia and cerebral malaria

    PMID:40143578

    Open questions at the time
    • Molecular link between GRASP, ATG8 autophagosomes and microneme elimination not defined
    • How Golgi function relates to the liver-stage/virulence phenotype is unresolved
    • Single lab; not confirmed in P. falciparum

Open questions

Synthesis pass · forward-looking unresolved questions
  • The biochemical function of GRASP in Golgi stacking, its direct partners, and the mechanism connecting its Golgi role to autophagosome-associated liver-stage regulation remain unknown.
  • No direct binding partners or substrates identified for PF3D7_1017300
  • No structural model
  • Mechanism of GRASP-mediated Golgi stacking in the parasite uncharacterized

Mechanism profile

Synthesis pass · controlled-vocabulary classification
No controlled-vocabulary terms were assigned to this entry.

Evidence

Reading pass · 5 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2005 PfGRASP (PF3D7_1017300) is expressed as a 70 kDa protein throughout the asexual life cycle of P. falciparum and localizes to a single, juxtanuclear compartment (Golgi apparatus) in ring-stage parasites. This localization is distinct from the ER, co-localizes with the cis-Golgi marker ERD2, and is insensitive to Brefeldin A. Correct subcellular localization depends on a cross-species conserved functional myristoylation motif. PfGRASP-GFP transgenic parasite live imaging, co-localization with ERD2, Brefeldin A treatment, mutagenesis of myristoylation motif Journal of cell science High 16306223
2008 GRASP (PF3D7_1017300) co-localizes with the cis-Golgi in a double-transfectant parasite line expressing GRASP-GFP and Rab6-DsRed, demonstrating that the cis- and trans-Golgi faces spatially separate during parasite maturation, and that Golgi multiplication is closely linked to transitional ER (tER) multiplication. Double-transfectant live-cell imaging (GRASP-GFP / Rab6-DsRed fusion parasites), co-localization analysis Molecular microbiology Medium 18284574
2008 P. falciparum expresses two GRASP isoforms from PF3D7_1017300 via a splice variant: GRASP1 relies on a conserved myristoylation motif for Golgi targeting, whereas GRASP2 has a different hydrophobic N-terminus resembling a signal anchor that mediates Golgi association through a distinct, fungi-like mechanism of membrane attachment. Identification of splice variant, GFP-fusion localization assays, N-terminus mutagenesis/deletion, phylogenetic analysis Journal of cell science Medium 18522993
2015 GRASP (PF3D7_1017300) was used as a Golgi marker to confirm that AlF4 treatment of P. falciparum shifts Pfμ1 (AP-1 adaptor) away from the Golgi to an ER-associated compartment, as evidenced by decreased co-localization with GRASP. This establishes GRASP as a bona fide Golgi resident marker in functional trafficking studies. Immunofluorescence co-localization of Pfμ1-GFP with GRASP, AlF4 pharmacological treatment Biochimica et biophysica acta Low 25573429
2025 In P. berghei, GRASP associates with PbATG8-positive autophagosomes containing micronemes during liver-stage development. Genetic knockout of PbGRASP shows no discernible phenotype in mosquito stages or asexual blood stage growth, but PbGRASP-KO liver stages form small schizonts at mid-infection followed by growth resumption. PbGRASP-KO hepatic merozoites egress normally but induce higher parasitemia with delayed and reduced cerebral malaria symptoms, indicating a regulatory role for GRASP in controlling parasite proliferation and virulence in the mammalian host. PbGRASP knockout (KO) parasites, live imaging of GRASP-autophagosome association, mouse infection models measuring parasitemia and cerebral malaria phenotype Molecular microbiology Medium 40143578

Source papers

Stage 0 corpus · 5 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 Re-defining the Golgi complex in Plasmodium falciparum using the novel Golgi marker PfGRASP. Journal of cell science 83 16306223
2008 Spatial dissection of the cis- and trans-Golgi compartments in the malaria parasite Plasmodium falciparum. Molecular microbiology 38 18284574
2008 Plasmodium falciparum possesses two GRASP proteins that are differentially targeted to the Golgi complex via a higher- and lower-eukaryote-like mechanism. Journal of cell science 32 18522993
2015 A role for adaptor protein complex 1 in protein targeting to rhoptry organelles in Plasmodium falciparum. Biochimica et biophysica acta 22 25573429
2025 The Plasmodium GRASP Homolog Modulates Liver Stage Development, Subsequent Blood Infection and Virulence in Mice. Molecular microbiology 0 40143578