GP2

GP2 (PF3D7_1123500) is a transmembrane Golgi-resident protein of Plasmodium falciparum that partners with Golgi Protein 1 (GP1) to form a Golgi Protein complex localizing to the cis-Golgi throughout the erythrocytic cycle, and potentially during mosquito stages (PMID:29579782). Gene inactivation of GP2, alone or combined with conditional repression of GP1, showed that this complex is dispensable for parasite viability at any life-cycle stage but is required for optimal asexual blood-stage development (PMID:29579782). Beyond its cis-Golgi localization, complex partnership with GP1, and this growth phenotype, no further molecular function, cargo, or mechanism for GP2 has been characterized in the available corpus.

1. 2018 Medium

   Establishing that PF3D7_1123500 is a bona fide Golgi component required demonstrating both its subcellular residence and a stable binding partner, defining it as a subunit of a discrete Golgi Protein complex rather than an isolated protein.

   Evidence Co-immunoprecipitation and fluorescence localization in P. falciparum strains

   PMID:29579782

   Open questions at the time

   • The molecular activity of GP2 within the complex is undefined
   • No cargo, substrate, or trafficking role assigned to the GP1-GP2 complex
   • Whether GP2 localization depends on GP1 (or vice versa) was not resolved
2. 2018 Medium

   Determining whether the Golgi Protein complex is required for the parasite answered its physiological importance: knockout of GP2 combined with GP1 repression showed the complex is non-essential for viability but supports optimal asexual blood-stage growth.

   Evidence Gene knockout of GP2 with conditional repression of GP1 and growth/development phenotyping in P. falciparum

   PMID:29579782

   Open questions at the time

   • The mechanistic basis of the suboptimal asexual growth defect is unknown
   • The specific Golgi function GP2 contributes to was not identified
   • Life-cycle stages beyond asexual blood stage were not phenotyped in detail

• The molecular function of GP2 within the cis-Golgi and the pathway by which its loss impairs asexual development remain unresolved.
• No enzymatic or trafficking activity assigned to GP2
• No cargo or downstream effectors of the GP1-GP2 complex identified
• No structural model of the complex or of GP2's transmembrane topology