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. As a scaffold protein may contribute to catalysis through positioning of the substrate and the ubiquitin-conjugating enzyme. The functional specificity of the E3 ubiquitin-protein ligase complex depends on the variable substrate recognition component. ECS(SOCS1) seems to direct ubiquitination of JAK2. 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. May form a cell surface vasopressin receptor. 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. Component of the probable ECS(LRRC41) complex with the substrate recognition component LRRC41. Component of the probable ECS(SOCS1) complex with the substrate recognition component SOCS1. Component of the probable ECS(WSB1) complex with the substrate recognition subunit WSB1. Component of the probable ECS(SOCS3) complex with the substrate recognition component SOCS3. Component of the probable ECS(SPSB1) complex with the substrate recognition component SPSB1. Component of the probable ECS(SPSB2) complex with the substrate recognition component SPSB2. Component of the probable ECS(SPSB4) complex with the substrate recognition component SPSB4. Component of the probable ECS(RAB40C) complex with the substrate recognition subunit RAB40C. Component of the probable ECS(KLHDC1) complex with the substrate recognition component KLHDC1. May also form complexes containing CUL5, elongin BC complex (ELOB and ELOC), RBX1 and ELOA. May also form complexes containing CUL5, Elongin BC (ELOB and ELOC), RBX1 and VHL. Interacts with RNF7/RBX2, LRRC41, SOCS3, SPSB1, SPSB2, SPSB4 and RAB40C. Interacts with ASB1, ASB2, ASB6, ASB7 and ASB12. Interacts (when neddylated) with ARIH2; leading to activate the E3 ligase activity of ARIH1. Interacts with NOS2 in the presence of SPSB1 or SPSB2 or SPSB4. Interacts with ERCC6; the interaction is induced by DNA damaging agents or inhibitors of RNA polymerase II elongation. Interacts with ELOA (via BC-box). Interacts (unneddylated form) with DCUN1D1, DCUN1D2, DCUN1D3, DCUN1D4 and DCUN1D5; these interactions promote the cullin neddylation. Kidney collecting tubules. 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.