RING finger, HC subclass, found in tripartite motif-containing protein 71 (TRIM71) and similar proteins
TRIM71, also known as protein lineage variant 41 (lin-41), is an E3 ubiquitin-protein ligase that may play essential roles in embryonic stem cells, cellular reprogramming and the timing of embryonic neurogenesis. It was first identified in the nematode Caenorhabditis elegans as a target of the differentiation-associated microRNA (miRNA) let-7 (lethal 7) and is therefore part of a heterochronic gene network that controls larval development. In humans, it regulates let-7 microRNA biogenesis via modulation of Lin28B protein polyubiquitination. TRIM71 localizes to cytoplasmic P-bodies and directly interacts with the miRNA pathway proteins Argonaute 2 (AGO2) and DICER. It represses miRNA activity by promoting degradative ubiquitination of AGO2. Moreover, TRIM71 associates with SHCBP1, a novel component of the fibroblast growth factor (FGF) signaling pathway, and regulates its non-degradative polyubiquitination. It is also involved in the post-transcriptional regulation of the CDKN1A, RBL1 and RBL2 or EGR1 mRNAs by mediating RNA-binding in embryonic stem cells. TRIM71 belongs to the C-VII subclass of the TRIM (tripartite motif)-NHL family that is defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as a NHL (named after proteins NCL-1, HT2A and Lin-41 that contain repeats folded into a six-bladed beta propeller) repeat domain positioned C-terminal to the RBCC domain.
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.",