| abstract |
PHD finger found in Transcription factor 19 (TCF-19), Lysine-specific demethylase KDM5A and KDM5B, and other similar proteins. TCF-19 was identified as a putative trans-activating factor with expression beginning at the late G1-S boundary in dividing cells. It functions as a novel islet factor necessary for proliferation and survival in the INS-1 beta cell line. It plays an important role in susceptibility to both Type 1 Diabetes Mellitus (T1DM) and Type 2 Diabetes Mellitus (T2DM); it has been suggested that it may positively impact beta cell mass under conditions of beta cell stress and increased insulin demand. KDM5A 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 interaction with TBP, p107, nuclear receptors, Myc, Sin3/HDAC, Mad1, RBP-J, CLOCK, and BMAL1. KDM5B 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. Both KDM5A and KDM5B function as trimethylated histone H3 lysine 4 (H3K4me3) demethylases. This family also includes Caenorhabditis elegans Lysine-specific demethylase 7 homolog (ceKDM7A). ceKDM7A (also termed JmjC domain-containing protein 1.2, PHD finger protein 8 homolog, or PHF8 homolog) is a plant homeodomain (PHD)- and JmjC domain-containing protein that functions as a histone demethylase specific for H3K9me2 and H3K27me2. The binding of the PHD finger to H3K4me3 guides H3K9me2- and H3K27me2-specific demethylation by its catalytic JmjC domain in a trans-histone regulation mechanism. In addition, this family includes plant protein OBERON 1 and OBERON 2, Alfin1-like (AL) proteins, histone acetyltransferases (HATs) HAC, and AT-rich interactive domain-containing protein 4 (ARID4). |