PHD finger 3 found in Lysine-specific demethylase 5A (KDM5A), 5B (KDM5B), and similar proteins
The family includes KDM5A and KDM5B, both of which belong to the JARID subfamily within the JmjC proteins. KDM5A, also termed Histone demethylase JARID1A, or Jumonji/ARID domain-containing protein 1A, or Retinoblastoma-binding protein 2 (RBBP-2 or RBP2), was originally identified as a retinoblastoma protein (Rb)-binding partner and its inactivation may be important for Rb to promote differentiation. It is involved in transcription through interacting with TBP, p107, nuclear receptors, Myc, Sin3/HDAC, Mad1, RBP-J, CLOCK and BMAL1. KDM5A functions as the trimethylated histone H3 lysine 4 (H3K4me3) demethylase. It also displays DNA-binding activities that can recognize the specific DNA sequence CCGCCC. KDM5B, also termed Cancer/testis antigen 31 (CT31), or Histone demethylase JARID1B, or Jumonji/ARID domain-containing protein 1B (JARID1B), or PLU-1, or retinoblastoma-binding protein 2 homolog 1 (RBP2-H1 or RBBP2H1A), has a restricted expression pattern in the testis, ovary, and transiently in the mammary gland of the pregnant female and has been shown to be upregulated in breast cancer, prostate cancer, and lung cancer, suggesting a potential role in tumorigenesis. KDM5B acts as a histone demethylase that catalyzes the removal of trimethylation of lysine 4 on histone H3 (H3K4me3), induced by polychlorinated biphenyls (PCBs). It also mediates demethylation of H3K4me2 and H3K4me1. Moreover, KDM5B functions as a negative regulator of hematopoietic stem cell (HSC) self-renewal and progenitor cell activity. KDM5B has also been shown to interact with the DNA binding transcription factors BF-1 and PAX9, as well asTIEG1/KLF10 (transforming growth factor-beta inducible early gene-1/Kruppel-like transcription factor 10), and possibly function as a transcriptional corepressor. The family also includes the Drosophila melanogaster protein little imaginal discs (Lid) that functions as a JmjC-dependent trimethyl histone H3K4 (H3K4me3) demethylase, which is required for dMyc-induced cell growth. It positively regulates Hox gene expression in S2 cells. Members in this family contain the catalytic JmjC domain, JmjN, the BRIGHT domain, which is an AT-rich interacting domain (ARID), and a Cys5HisCys2 zinc finger, as well as three plant homeodomain (PHD) fingers. This model corresponds to the third PHD finger.
Jiyao W et al.(2023). "The conserved domain database in 2023.",