CAF1B

PF3D7_1329300 (CAF1B) is a subunit of the Plasmodium falciparum chromatin assembly factor 1 (CAF1) complex that functions as a histone chaperone in heterochromatin maintenance and nucleosome assembly (PMID:29183721). Within this complex it associates with PfCAF2, histones, and the heterochromatin protein PfHP1, and it co-localizes with PfHP1 at telomeric repeat regions and subtelomeric and central var gene loci, linking it to the chromatin organization that underlies var gene silencing (PMID:29183721). Its upregulation following genotoxic treatment implicates the complex in DNA damage responses (PMID:29183721). Beyond its CAF1 membership, CAF1B is detected as a proximity interactor of the histone methyltransferase PfSET10 in blood-stage nuclei, placing it within a broader nuclear chromatin-remodeling network (PMID:39445823). No direct functional characterization of CAF1B itself — through mutagenesis, in vitro reconstitution, or gene disruption — has been reported in the available corpus.

1. 2017 Medium

   Establishing whether PF3D7_1329300 participates in Plasmodium chromatin organization required defining its physical partners and genomic occupancy; this work placed it in the CAF1 histone chaperone complex at heterochromatic loci.

   Evidence Co-immunoprecipitation with PfCAF2, histones, and PfHP1, plus ChIP at telomeric and var gene loci and upregulation after MMS/HU treatment, in P. falciparum

   PMID:29183721

   Open questions at the time

   • No in vitro reconstitution or mutagenesis to confirm a direct histone-chaperone activity for CAF1B specifically
   • Contribution of CAF1B relative to other complex subunits to var gene silencing is not resolved
   • The mechanistic link between genotoxic upregulation and a defined DNA damage repair role is not established
2. 2024 Low

   Whether CAF1B connects to other chromatin-modifying machineries was addressed by proximity mapping around PfSET10, extending its network beyond the CAF1 complex.

   Evidence TurboID proximity-labeling coupled with mass spectrometry in PfSET10-KO/KD lines, in P. falciparum

   PMID:39445823

   Open questions at the time

   • Proximity labeling establishes association but not a direct or functional CAF1B–PfSET10 interaction
   • No functional consequence of the CAF1B–PfSET10 association was tested
   • Does not distinguish a role for CAF1B from other network members detected in the same experiment

• The intrinsic biochemical activity of CAF1B and its non-redundant contribution to nucleosome assembly, var gene silencing, and DNA damage responses remain undefined.
• No targeted gene disruption or conditional knockdown of CAF1B itself
• No structural or reconstituted-complex data assigning function to CAF1B
• Direct histone-binding activity of CAF1B has not been demonstrated in isolation