RAB2

PF3D7_1231100 (RAB2) is a Rab-family GTPase of Plasmodium falciparum implicated in vesicular trafficking; it is transcribed across the intraerythrocytic stages, where it was originally assigned by phylogenetic comparison a role in vacuole size regulation, though only transcription was experimentally confirmed (PMID:12657463). Direct functional characterization of the parasite's own RAB2 protein is absent from the available corpus: the mechanistic evidence linking Rab2 to membrane trafficking derives from mammalian Rab2, which recruits P. falciparum GAPDH to microsomal membranes via the GAPDH N-terminal domain (residues 1–192) in a heterologous binding assay establishing conservation of the recruitment mechanism rather than an activity of PF3D7_1231100 itself (PMID:12974391). Within the parasite, RAB2 protein is upregulated under proteasomal stress (PMID:26136076) and was recovered as a putative co-immunoprecipitating partner of the casein kinase PfCK1 (PMID:26629826), and in silico network analysis places it alongside ERD2 and Rab1 as a candidate regulator of COPII-dependent ER-to-Golgi trafficking (PMID:30704415). Beyond these correlative, heterologous, and computational observations, no direct in vivo functional experiment on PF3D7_1231100 has been characterized in the available corpus.

1. 2003 Low

   Establishing whether RAB2 is expressed at all in the blood stage was the first prerequisite for any functional hypothesis; transcription testing confirmed it is expressed and, by analogy to yeast, tentatively assigned a trafficking/vacuole role.

   Evidence Experimental transcription testing plus phylogenetic comparison across the P. falciparum Rab family in infected erythrocytes

   PMID:12657463

   Open questions at the time

   • Vacuole-size role is pure phylogenetic inference with no functional assay
   • No protein-level detection or localization of RAB2
   • No GTPase activity demonstrated
2. 2003 Medium

   To test whether Rab2-dependent membrane recruitment is conserved for a Plasmodium substrate, GAPDH recruitment was reconstituted heterologously, showing pfGAPDH binds microsomal membranes in a Rab2-dependent manner through its N-terminal domain.

   Evidence Quantitative HeLa microsomal membrane binding assay with mammalian Rab2 and competitive inhibition by recombinant pfGAPDH fragments (residues 1–192)

   PMID:12974391

   Open questions at the time

   • Used mammalian Rab2, not PF3D7_1231100, so the activity is not demonstrated for the parasite protein
   • No evidence this interaction occurs in the parasite
   • Functional consequence of GAPDH recruitment unresolved
3. 2015 Low

   Whether RAB2 responds to cellular stress was probed by global proteomics, revealing upregulation of RAB2 protein under proteasome inhibition and hinting at increased trafficking as a homeostatic response.

   Evidence Quantitative global proteomics of proteasome-inhibitor-treated P. falciparum parasites

   PMID:26136076

   Open questions at the time

   • Correlative abundance change only, no functional manipulation
   • Mechanism linking proteasomal stress to RAB2 levels unknown
4. 2015 Low

   To place RAB2 in a signaling context, PfCK1 interactome profiling recovered RAB2 as a putative partner, connecting it to kinase-regulated trafficking pathways.

   Evidence Co-immunoprecipitation/mass spectrometry from parasites expressing tagged PfCK1

   PMID:26629826

   Open questions at the time

   • Single Co-IP/MS without reciprocal pulldown
   • No validation that RAB2 is a direct PfCK1 substrate or binder
   • No functional follow-up on RAB2
5. 2019 Low

   A computational attempt to assign RAB2 to a defined trafficking step predicted it, with ERD2 and Rab1, as a COPII regulatory protein in ER-to-Golgi transport.

   Evidence In silico protein interaction network analysis of P. falciparum COPII complexes

   PMID:30704415

   Open questions at the time

   • Purely computational, no experimental validation of RAB2–COPII association
   • No demonstration of RAB2 localization to ER-Golgi membranes
6. 2021 Low

   Testing whether the host-cell Rab2 trafficking machinery is required by intracellular parasites, dominant-negative host Rab2a caused only a transient early liver-stage delay in P. berghei, indicating host Rab2 is largely dispensable and leaving the parasite's own RAB2 untested.

   Evidence Bioluminescence imaging of P. berghei liver-stage parasites in HeLa cells expressing dominant-negative host Rab2a

   PMID:34013963

   Open questions at the time

   • Tests host-cell Rab2a, not parasite PF3D7_1231100
   • Different species (P. berghei) and life-cycle stage than the blood-stage RAB2 findings
   • Minor/negative phenotype limits interpretation

• No direct in vivo functional experiment has been performed on the parasite's own RAB2 protein; its GTPase activity, membrane localization, effectors, and role in COPII/ER-to-Golgi trafficking within the parasite remain uncharacterized.
• No knockout, knockdown, or conditional depletion of PF3D7_1231100
• No demonstrated GTPase activity or GEF/GAP/effector for the parasite protein
• No direct subcellular localization of RAB2 in P. falciparum