RING finger, HC subclass, found in RING finger protein 8 (RNF8) and similar proteins
RNF8 is a telomere-associated E3 ubiquitin-protein ligase that plays an important role in DNA double-strand break (DSB) repair via histone ubiquitination. It is localized in the nucleus and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3), but not with other E2s (UbcH5, UbcH7, UbcH10, hCdc34, and hBendless). It recruits UBC13 for lysine 63-based self polyubiquitylation. Its deficiency causes neuronal pathology and cognitive decline, and its loss results in neuron degeneration. RNF8, together with RNF168, catalyzes a series of ubiquitylation events on substrates such as H2A and H2AX, with the H2AK13/15 ubiquitylation being particularly important for recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of DSBs. RNF8 mediates the ubiquitination of gammaH2AX, and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DNA damage response (DDR) and inhibits chromosomal instability. Moreover, RNF8 interacts with retinoid X receptor alpha (RXR alpha) and enhances its transcription-stimulating activity. It also regulates the rate of exit from mitosis and cytokinesis. RNF8 contains an N-terminal forkhead-associated (FHA) domain and a C-terminal C3HC4-type RING-HC finger.
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.",