EIF5

PF3D7_1206700 (EIF5) is a putative eukaryotic translation initiation factor of P. falciparum whose characterized role is participation in the translation initiation machinery through a physical interaction with PfeIF2β, established by binding assays with wild-type and mutated PfeIF2β (PMID:27303372). Beyond this interaction, no catalytic activity, substrate, or functional consequence has been experimentally defined for EIF5 in the available corpus. The protein is detected as phosphorylated during intraerythrocytic asexual blood-stage development (PMID:33517144), but the responsible kinase and the functional impact of this modification have not been characterized.

1. 2016 Medium

   To place EIF5 within the parasite's translation initiation apparatus, its physical association with a core eIF2 subunit was tested, establishing that EIF5 interacts with PfeIF2β and thereby participates in the translation initiation complex.

   Evidence Direct binding/pull-down assays using wild-type and mutated PfeIF2β, with functional validation in a Xenopus oocyte system

   PMID:27303372

   Open questions at the time

   • Single binding assay from one lab without reciprocal or orthogonal validation
   • The functional consequence of the EIF5–PfeIF2β interaction for translation initiation is not defined
   • The binding interface and stoichiometry on EIF5 itself are not mapped
2. 2020 Low

   To ask whether EIF5 is post-translationally regulated during blood-stage growth, a proteome-wide PTM survey detected EIF5 as phosphorylated in intraerythrocytic stages, indicating it is a substrate for phosphorylation during asexual development.

   Evidence Proteome-wide mass spectrometry-based PTM profiling of P. falciparum intraerythrocytic stages

   PMID:33517144

   Open questions at the time

   • Large-scale catalog detection with no functional follow-up specific to EIF5
   • Responsible kinase and phosphosite occupancy are unknown
   • Effect of phosphorylation on EIF5 activity or complex assembly is undetermined

• Whether EIF5 has an intrinsic biochemical activity in translation initiation, and how its PfeIF2β interaction and phosphorylation contribute to parasite protein synthesis, remains unresolved.
• No loss-of-function or essentiality data for EIF5
• No structural model of EIF5 or its complex
• No link between phosphorylation state and interaction with PfeIF2β