Human Casitas B-lineage lymphoma proto-oncogene b (CBL-B), also known as E3 ubiquitin-protein ligase CBL-B, RING finger protein 56, and SH3- binding protein CBL-B with Y363F mutation GenBank Accession No. NM_170662, a.a. 39 – 426 with N-terminal His-tag and N-terminal Avi-tag, expressed in an E. coli expression system. This protein was enzymatically biotinylated in vivo using AviTagTM technology. MW=48 kDa.