RING finger, HC subclass, found in SH3 domain-containing RING finger proteins SH3RF1, SH3RF2, SH3RF3, and similar proteins
SH3RF1, also known as plenty of SH3s (POSH), RING finger protein 142 (RNF142), or SH3 multiple domains protein 2 (SH3MD2), is a trans-Golgi network-associated pro-apoptotic scaffold protein with E3 ubiquitin-protein ligase activity. SH3RF2, also known as heart protein phosphatase 1-binding protein (HEPP1), plenty of SH3s (POSH)-eliminating RING protein (POSHER), protein phosphatase 1 regulatory subunit 39, or RING finger protein 158 (RNF158), is a putative E3 ubiquitin-protein ligase that acts as an anti-apoptotic regulator for the c-Jun N-terminal kinase (JNK) pathway by binding to and promoting the proteasomal degradation of SH3RF1 (or POSH) that is required for pro-apoptotic JNK activation. SH3RF3, also known as plenty of SH3s 2 (POSH2) or SH3 multiple domains protein 4 (SH3MD4), is a scaffold protein with E3 ubiquitin-protein ligase activity. It was identified in the screen for interacting partners of p21-activated kinase 2 (PAK2) and may play a role in regulating c-Jun N-terminal kinase (JNK) mediated apoptosis in certain conditions. Members of this subfamily contain an N-terminal C3HC4-type RING-HC finger responsible for the E3 ligase activity and four Src Homology 3 (SH3) domains, which are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs.
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.",