Protein fem-1 homolog B

UniProtKB accession:  Q9Z2G0

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Substrate-recognition component of a Cul2-RING (CRL2) E3 ubiquitin-protein ligase complex of the DesCEND (destruction via C-end degrons) pathway, which recognizes a C-degron located at the extreme C terminus of target proteins, leading to their ubiquitination and degradation (By similarity). The C-degron recognized by the DesCEND pathway is usually a motif of less than ten residues and can be present in full-length proteins, truncated proteins or proteolytically cleaved forms (By similarity). The CRL2(FEM1B) complex specifically recognizes proteins ending with -Gly-Leu-Asp-Arg, such as CDK5R1, leading to their ubiquitination and degradation (By similarity). Also acts as a regulator of the reductive stress response by mediating ubiquitination of reduced FNIP1: in response to reductive stress, the CRL2(FEM1B) complex specifically recognizes a conserved Cys degron in FNIP1 when this degron is reduced, leading to FNIP1 degradation and subsequent activation of mitochondria to recalibrate reactive oxygen species (ROS) (PubMed:32941802, PubMed:34562363). Mechanistically, recognizes and binds reduced FNIP1 through two interface zinc ions, which act as a molecular glue that recruit reduced FNIP1 to FEM1B (PubMed:34562363). Promotes ubiquitination of GLI1, suppressing GLI1 transcriptional activator activity (By similarity). Promotes ubiquitination and degradation of ANKRD37 (PubMed:21723927). Promotes ubiquitination and degradation of SLBP (By similarity). Involved in apoptosis by acting as a death receptor-associated protein that mediates apoptosis (By similarity). Also involved in glucose homeostasis in pancreatic islet (PubMed:16024793). May also act as an adapter/mediator in replication stress-induced signaling that leads to the activation of CHEK1 (By similarity).