B-box-type 2 zinc finger found in tripartite motif-containing proteins, TRIM9, TRIM67 and similar proteins
This family includes a group of tripartite motif-containing proteins including TRIM9 and TRIM67, both of which belong to the C-I subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, consisting of three consecutive zinc-binding domains, a RING finger, Bbox1 and Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, a fibronectin type III (FN3) domain, and a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. The type 2 B-box (Bbox2) zinc finger is characterized by a CHC3H2 zinc-binding consensus motif. TRIM9 (the human ortholog of rat Spring), also known as RING finger protein 91 (RNF91), is a brain-specific E3 ubiquitin-protein ligase collaborating with an E2 ubiquitin conjugating enzyme UBCH5b. It plays an important role in the regulation of neuronal functions and participates in neurodegenerative disorders through its ligase activity. TRIM67, also termed TRIM9-like protein (TNL), is a protein selectively expressed in the cerebellum. It interacts with PRG-1, an important molecule in the control of hippocampal excitability dependent on presynaptic LPA2 receptor signaling, and 80K-H (also known as glucosidase II beta), a protein kinase C substrate. It negatively regulates Ras signaling in cell proliferation via degradation of 80K-H, leading to neural differentiation including neuritogenesis.
Jiyao W et al.(2023). "The conserved domain database in 2023.",