May negatively regulate the 4-1BB-mediated signaling cascades which result in the activation of NK-kappaB and JNK1. Probable substrate recognition subunit of an ECS (Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Protein modification; protein ubiquitination. Interacts with the cytoplasmic domain of TNFRSF9. Component of the probable ECS(LRR1) E3 ubiquitin-protein ligase complex which contains CUL2, RBX1, Elongin BC complex and LRR1. Interacts with CUL2, RBX1, ELOB and ELOC. Ubiquitous. Maximal expression was seen in the heart and skeletal muscle and minimal expression seen in the kidney. Extended N-terminus.