Core component of multiple SCF-like ECS (Elongin-Cullin 2/5-SOCS-box protein) E3 ubiquitin-protein ligase complexes, which mediate the ubiquitination and subsequent proteasomal degradation of target proteins (PubMed:11384984, PubMed:15601820). As a scaffold protein may contribute to catalysis through positioning of the substrate and the ubiquitin-conjugating enzyme (PubMed:11384984, PubMed:15601820). The functional specificity of the E3 ubiquitin-protein ligase complex depends on the variable substrate recognition component (PubMed:11384984, PubMed:15601820). ECS(SOCS1) seems to direct ubiquitination of JAK2 (PubMed:11384984). ECS(KLHDC1) complex is part of the DesCEND (destruction via C-end degrons) pathway and mediates ubiquitination and degradation of truncated SELENOS selenoprotein produced by failed UGA/Sec decoding, which ends with a glycine (PubMed:32200094). May form a cell surface vasopressin receptor (PubMed:9037604). (Microbial infection) Seems to be involved in proteosomal degradation of p53/TP53 stimulated by adenovirus E1B-55 kDa protein. Protein modification; protein ubiquitination. Component of multiple ECS (Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin-protein ligase complexes formed of CUL5, Elongin BC (ELOB and ELOC), RBX2 and a variable SOCS box domain-containing protein as substrate-specific recognition component (PubMed:11384984, PubMed:15601820). Component of the probable ECS(LRRC41) complex with the substrate recognition component LRRC41 (PubMed:11384984). Component of the probable ECS(SOCS1) complex with the substrate recognition component SOCS1 (PubMed:11384984). Component of the probable ECS(WSB1) complex with the substrate recognition subunit WSB1 (PubMed:15601820). Component of the probable ECS(SOCS3) complex with the substrate recognition component SOCS3 (PubMed:15601820). Component of the probable ECS(SPSB1) complex with the substrate recognition component SPSB1 (PubMed:15601820). Component of the probable ECS(SPSB2) complex with the substrate recognition component SPSB2 (PubMed:15601820). Component of the probable ECS(SPSB4) complex with the substrate recognition component SPSB4 (PubMed:15601820). Component of the probable ECS(RAB40C) complex with the substrate recognition subunit RAB40C (PubMed:15601820). Component of the probable ECS(KLHDC1) complex with the substrate recognition component KLHDC1 (PubMed:32200094). May also form complexes containing CUL5, elongin BC complex (ELOB and ELOC), RBX1 and ELOA (PubMed:11384984). May also form complexes containing CUL5, Elongin BC (ELOB and ELOC), RBX1 and VHL (PubMed:10230407, PubMed:18805092). Interacts with RNF7/RBX2, LRRC41, SOCS3, SPSB1, SPSB2, SPSB4 and RAB40C (PubMed:15601820). Interacts with ASB1, ASB2, ASB6, ASB7 and ASB12 (PubMed:16325183, PubMed:21119685). Interacts (when neddylated) with ARIH2; leading to activate the E3 ligase activity of ARIH1 (PubMed:24076655). Interacts with NOS2 in the presence of SPSB1 or SPSB2 or SPSB4 (PubMed:21199876). Interacts with ERCC6; the interaction is induced by DNA damaging agents or inhibitors of RNA polymerase II elongation (PubMed:28292928). Interacts with ELOA (via BC-box) (PubMed:28292928). Interacts (unneddylated form) with DCUN1D1, DCUN1D2, DCUN1D3, DCUN1D4 and DCUN1D5; these interactions promote the cullin neddylation (PubMed:23201271, PubMed:26906416). (Microbial infection) Interacts (via the substrate recognition component) with HIV-1 Vif. (Microbial infection) Interacts (via the substrate recognition component) with human adenovirus 5 proteins E1B-55K and E4-orf6. (Microbial infection) Interacts with herpes virus 8 protein LANA1; this interaction promotes the degradation of NF-kappa-B component RELA. (Microbial infection) Interacts with molluscum contagiosum virus protein MC132; this interaction promotes the degradation of NF-kappa-B component RELA. Neddylated; which enhances the ubiquitination activity of SCF and prevents binding of the inhibitor CAND1. Deneddylated via its interaction with the COP9 signalosome (CSN). Belongs to the cullin family.