PHD finger found in BRPF proteins, Jade proteins, protein AF-10, AF-17, and similar proteins
The family includes BRPF proteins, Jade proteins, protein AF-10 and AF-17. BRPF proteins are scaffold proteins that form monocytic leukemic zinc-finger protein (MOZ)/MOZ-related factor (MORF) H3 histone acetyltransferase (HAT) complexes with other regulatory subunits, such as inhibitor of growth 5 (ING5) and Esa1-associated factor 6 ortholog (EAF6). BRPF proteins have multiple domains, including a canonical Cys4HisCys3 plant homeodomain (PHD) zinc finger followed by a non-canonical extended PHD (ePHD) finger, Cys2HisCys5HisCys2His, a bromodomain and a proline-tryptophan-tryptophan-proline (PWWP) domain. PHD and ePHD fingers both bind to lysine 4 of histone H3 (K4H3), bromodomains interact with acetylated lysines on N-terminal tails of histones and other proteins, and PWWP domains show histone-binding and chromatin association properties. Jade proteins are required for ING4 and ING5 to associate with histone acetyltransferase (HAT) HBO1 and EAF6, to form a HBO1 complex that has a histone H4-specific acetyltransferase activity, a reduced activity toward histone H3, and is responsible for the bulk of histone H4 acetylation in vivo. AF-10, also termed ALL1 (acute lymphoblastic leukemia)-fused gene from chromosome 10 protein, is a transcription factor that has been implicated in the development of leukemia following chromosomal rearrangements between the AF10 gene and one of at least two other genes, MLL and CALM. AF-17, also termed ALL1-fused gene from chromosome 17 protein, is a putative transcription factor that may play a role in multiple signaling pathways. All Jade proteins, AF-10, and AF-17 contain a canonical PHD finger followed by a non-canonical ePHD finger. This model corresponds to the canonical PHD finger.