RING finger, HC subclass, found in RING finger protein RNF20, RNF40, and similar proteins
RNF20, also known as BRE1A, and RNF40, also known as BRE1B, are E3 ubiquitin-protein ligases that work together to form a heterodimeric complex that facilitate the K120 monoubiquitination of histone H2B (H2Bub1), a DNA damage-induced histone modification that is crucial for recruitment of the chromatin remodeler SNF2h to DNA double-strand break (DSB) damage sites. RNF20 regulates the cell cycle and differentiation of neural precursor cells (NPCs) and links histone H2B ubiquitylation with inflammation and inflammation-associated cancer. RNF40, also known as 95 kDa retinoblastoma-associated protein (RBP95), was identified as a novel leucine zipper retinoblastoma protein (pRb)-associated protein that may function as a regulation factor in RNA polymerase II-mediated transcription and/or transcriptional processing. All subfamily members contain a C3HC4-type RING-HC finger at its C-terminus.
Comment:C3HC4-type RING-HC finger consensus motif: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, where X is any amino acid and the number of X residues varies in different fingers
Comment:A RING finger typically binds two zinc atoms, with its Cys and/or His side chains in a unique "cross-brace" arrangement.
Jiyao W et al.(2023). "The conserved domain database in 2023.",