Chromatin assembly factor 1 (CAF1) is the only histone chaperone known to assemble histones H3 and H4 onto newly synthesized DNA both in vitro and in vivo [PMID:17065558]. The 938 amino acid multidomain p150 (CHAF1A) binds via its C-terminal third to p60, which is an essential step for nucleosome assembly because knocking down either subunit disrupts the activity [PMID:14519857]. In addition, CAF1 facilitates DNA synthesis depending on the binding of the N-terminal 31 residues of p150 to the proliferating cell nuclear antigen (PCNA), which acts as a sliding clamp to stimulate the processivity of DNA polymerase [PMID:10648606]. CHAF1A regulates the formation of heterochromatin in mammalian cells during replication and in plants it maintains the transcription of certain subsets of genes. Furthermore, CHAF1A exists in a chromatin-remodeling complex WINAC, which coactivates ligand-induced transactivation function of the vitamin D receptor [PMID:12837248]. CHAF1A protein exists some phosphorylation sites, which may affect its theoretical molecular weight when tested.And a 150 kDa band was recognized (PMID:27445493).