PHD finger 4 found in Histone-lysine N-methyltransferase 2C (KMT2C) and PHD domain 3 found in KMT2D
KMT2C, also termed myeloid/lymphoid or mixed-lineage leukemia protein 3 (MLL3) or homologous to ALR protein, is a histone H3 lysine 4 (H3K4) lysine methyltransferase that functions as a circadian factor contributing to genome-scale circadian transcription. It is a component of a large complex that acts as a coactivator of multiple transcription factors, including the bile acid (BA)-activated nuclear receptor, farnesoid X receptor (FXR), a critical player in BA homeostasis. The MLL3 complex is essential for p53 transactivation of small heterodimer partner (SHP). KMT2C is also a part of activating signal cointegrator-2 (ASC-2)-containing complex (ASCOM) that contains the transcriptional coactivator nuclear receptor coactivator 6 (NCOA6), KMT2C and its paralog MLL4. The ASCOM complex is critical for nuclear receptor (NR) activation of bile acid transporter genes and is down regulated in cholestasis. KMT2D, also termed ALL1-related protein (ALR), is encoded by the gene that was named MLL4, a fourth human homolog of Drosophila trithorax, located on chromosome 12. It enzymatically generates trimethylated histone H3 Lysine 4 (H3K4me3). It plays an essential role in differentiating the human pluripotent embryonal carcinoma cell line NTERA-2 clone D1 (NT2/D1) stem cells by activating differentiation-specific genes, such as HOXA1-3 and NESTIN. KMT2D is also a part of ASCOM. Both KMT2C and KMT2D contain the catalytic domain SET, several plant homeodomain (PHD) fingers, two extended PHD (ePHD) fingers, Cys2HisCys5HisCys2His, two extended PHD (ePHD) fingers, a RING finger, an HMG (high-mobility group)-binding motif, and two FY-rich regions. This model corresponds to the fourth PHD finger of KMT2C and the third domain of KMT2D.
Jiyao W et al.(2023). "The conserved domain database in 2023.",