RBAP46

PF3D7_1433300 (RBAP46) is a putative histone chaperone of asexual blood-stage Plasmodium falciparum that is expressed across all three asexual blood stages and localizes to the nucleus (PMID:32363442). Purified recombinant PF3D7_1433300 directly binds histone H4 in vitro, identifying histone H4 as a physical interaction partner and pointing to a role in chromatin maintenance (PMID:32363442). Beyond its nuclear localization and direct H4 binding, no functional role, complex membership, or in vivo phenotype for PF3D7_1433300 has been characterized in the available corpus.

1. 2020 Medium

   Whether PF3D7_1433300 is expressed and where it acts in the parasite was unknown; establishing stage-specific expression and nuclear localization positioned it as a candidate chromatin-associated factor in blood-stage parasites.

   Evidence Cloning, recombinant expression in E. coli, and subcellular localization by direct imaging in P. falciparum

   PMID:32363442

   Open questions at the time

   • No functional consequence tied to the nuclear localization
   • No identification of the chromatin-regulatory complex it associates with in vivo
   • Single-lab observation
2. 2020 Medium

   Whether PF3D7_1433300 physically engages histones was unknown; demonstrating direct binding to histone H4 established a candidate molecular substrate and supported a histone-chaperone function.

   Evidence In vitro binding assay with purified recombinant protein and histone H4

   PMID:32363442

   Open questions at the time

   • Single method and single lab, no reciprocal or in-cell validation of the interaction
   • Binding affinity and stoichiometry not determined
   • No demonstration that H4 binding matters for any parasite chromatin process
3. 2020 Low

   Whether the parasite protein retains the structural features underlying histone recognition was addressed by modeling its predicted fold against human RBBP7.

   Evidence Comparative in silico sequence and homology structural analysis

   PMID:32363442

   Open questions at the time

   • Computational prediction only; no experimental structure or mutagenesis of the predicted histone-binding pocket
   • Species-specific pocket residue differences not functionally tested
   • Fold not confirmed by structural determination

• The specific chromatin-regulatory complex(es) PF3D7_1433300 operates within in P. falciparum, and its in vivo function and essentiality, remain unestablished.
• No complex membership defined for PF3D7_1433300 itself
• No genetic knockdown/knockout phenotype reported
• No demonstrated role in a defined chromatin process