SH3 Domain Containing Ring Finger Protein 1 (SH3RF1)

SH3RF1 encodes a protein containing an N-terminus RING-finger, four SH3 domains, and a region implicated in binding of the Rho GTPase Rac. Via the RING-finger, the encoded protein has been shown to function as an ubiquitin-protein ligase involved in protein sorting at the trans-Golgi network. The encoded protein may also act as a scaffold for the c-Jun N-terminal kinase signaling pathway, facilitating the formation of a functional signaling module. This protein consists of four SH3 domains and ectopic expression leads to the activation of the JNK pathway and to nuclear translocation of NF-kappaB. When overexpressed in fibroblasts, POSH is a strong inducer of apoptosis. POSH acts as a scaffold protein and contributes to Rac-induced signal transduction pathways leading to diverse gene transcriptional changes.