ALP2b

ALP2b (PF3D7_0505200) is a putative actin-like protein whose only characterized role in the available corpus is as a co-purifying component of chromatin remodeling complexes. In P. falciparum, ALP2b was detected as part of the PfSWR1 complex through affinity pulldown of the shared NuA4/SWR1 subunit PfEAF2 followed by mass spectrometry (PMID:38564734). In P. berghei, its ortholog (PBANKA_1104800) co-immunoprecipitated with PbARID, a subunit of a SWI/SNF chromatin remodeling complex, placing it among the actin-related proteins that may associate with the ATPase subunit gSNF2 via an HSA domain (PMID:38554111). Beyond this complex membership, no direct functional characterization of ALP2b — its biochemical activity, direct binding partners, or a specific role separable from the complex — has been reported in the available corpus.

1. 2024 Low

   Establishing the physical context of ALP2b addressed whether this putative actin-like protein associates with nuclear chromatin machinery, by placing it within the PfSWR1 remodeling complex.

   Evidence Affinity pulldown with PfEAF2 bait followed by mass spectrometry in P. falciparum

   PMID:38564734

   Open questions at the time

   • Single pulldown/MS identification with no reciprocal pulldown, mutagenesis, or functional validation specific to ALP2b
   • Direct binding partner within the complex not established
   • Whether ALP2b has a role separable from the complex is unknown
2. 2024 Low

   The orthologous finding tested whether ALP2b's complex association is conserved, showing the P. berghei ortholog co-purifies with a SWI/SNF subunit and may contact the gSNF2 ATPase.

   Evidence Co-immunoprecipitation with PbARID bait followed by mass spectrometry (RIME) in P. berghei

   PMID:38554111

   Open questions at the time

   • Single co-IP/MS identification with no direct binding assay for ALP2b with gSNF2
   • HSA-domain-mediated interaction inferred, not demonstrated for this protein
   • No functional or phenotypic assay of ALP2b loss

• Whether ALP2b performs any specific molecular function within these remodeling complexes — and whether it is essential, structural, or regulatory — remains unresolved.
• No direct binding assay confirming interaction with gSNF2 or other subunits
• No genetic knockout/knockdown phenotype for ALP2b
• No biochemical demonstration of actin-like activity