Regulatory component of cullin-RING-based SCF (SKP1-Cullin-F-box protein) E3 ubiquitin-protein ligase complexes (PubMed:22405651, PubMed:22748924). Inhibits E3 ubiquitin ligase activity by binding to RBX1 (via RING domain) and inhibiting its interaction with the E2 ubiquitin-conjugating enzyme CDC34 (PubMed:22405651, PubMed:22748924). Inhibits RBX1-mediated neddylation of CUL1 (PubMed:22405651). Required for normal stability and normal cellular levels of key components of SCF ubiquitin ligase complexes, including FBXW7, RBX1, CUL1, CUL2, CUL3, CUL4A, and thereby contributes to the regulation of CCNE1 and MYC levels (By similarity). Essential for normal development of the vasculature (PubMed:11845407). Contributes to the regulation of RPS6KB1 phosphorylation (PubMed:11571281). Interacts with FKBP4 and FKBP1A (PubMed:8955134, PubMed:12604780, PubMed:11164950). Isoform 1: Interacts with RBX1 (via RING domain) (PubMed:22405651, PubMed:22748924). Identified in complexes that contain RBX1 plus one of the cullins CUL1, CUL2, CUL3, and CUL4A (PubMed:22405651, PubMed:22748924). Identified in a SCF complex composed of CUL1, RBX1, SKP1, FBXW7 and GLMN (PubMed:22405651). Component of a SCF-like complex consisting of CUL7, RBX1, SKP1, FBXW8 and GLMN (PubMed:12904573). Interacts with unphosphorylated MET and is released upon MET phosphorylation (PubMed:11571281). Ubiquitous. The C-terminal half of the protein is important for interaction with RBX1. Phosphorylated on tyrosine residues. The disease is caused by variants affecting the gene represented in this entry.