Core component of the 3M and Cul7-RING(FBXW8) complexes, which mediate the ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:12481031, PubMed:12904573, PubMed:21572988, PubMed:21737058, PubMed:24793695, PubMed:35982156). Core component of the 3M complex, a complex required to regulate microtubule dynamics and genome integrity (PubMed:21572988, PubMed:21737058, PubMed:24793695). It is unclear how the 3M complex regulates microtubules, it could act by controlling the level of a microtubule stabilizer (PubMed:24793695). The Cul7-RING(FBXW8) complex alone lacks ubiquitination activity and does not promote polyubiquitination and proteasomal degradation of p53/TP53 (PubMed:16547496, PubMed:17332328, PubMed:35982156). However it mediates recruitment of p53/TP53 for ubiquitination by neddylated CUL1-RBX1 (PubMed:35982156). Interaction with CUL9 is required to inhibit CUL9 activity and ubiquitination of BIRC5 (PubMed:24793696). The Cul7-RING(FBXW8) complex also mediates ubiquitination and consequent degradation of target proteins such as GORASP1, IRS1 and MAP4K1/HPK1 (PubMed:21572988, PubMed:24362026). Ubiquitination of GORASP1 regulates Golgi morphogenesis and dendrite patterning in brain (PubMed:21572988). Mediates ubiquitination and degradation of IRS1 in a mTOR-dependent manner: the Cul7-RING(FBXW8) complex recognizes and binds IRS1 previously phosphorylated by S6 kinase (RPS6KB1 or RPS6KB2) (PubMed:18498745). The Cul7-RING(FBXW8) complex also mediates ubiquitination of MAP4K1/HPK1: recognizes and binds autophosphorylated MAP4K1/HPK1, leading to its degradation, thereby affecting cell proliferation and differentiation (PubMed:24362026). Acts as a regulator in trophoblast cell epithelial-mesenchymal transition and placental development (PubMed:20139075). While the Cul7-RING(FBXW8) and the 3M complexes are associated and involved in common processes, CUL7 and the Cul7-RING(FBXW8) complex may have additional functions. Probably plays a role in the degradation of proteins involved in endothelial proliferation and/or differentiation. {ECO:0000269|PubMed:12481031, ECO:0000269|PubMed:12904573, ECO:0000269|PubMed:16547496, ECO:0000269|PubMed:17332328, ECO:0000269|PubMed:18498745, ECO:0000269|PubMed:20139075, ECO:0000269|PubMed:21572988, ECO:0000269|PubMed:21737058, ECO:0000269|PubMed:24362026, ECO:0000269|PubMed:24793695, ECO:0000269|PubMed:24793696, ECO:0000269|PubMed:35982156}. This is the function of ENSG00000044090 (CUL7, cullin 7).