SH3 Domain Kinase Binding Protein 1 (SH3KBP1)

CBL constitutively interacts with SH3 domain-containing proteins and, upon tyrosine phosphorylation, with SH2 domain-containing proteins. The SH3KBP1 gene encodes an 85-kD CBL-interacting protein that enhances tumor necrosis factor-mediated apoptotic cell death.Sequence analysis predicted that the 665-amino acid protein, 36% identical to CMS, contains 3 consecutive N-terminal SH3 domains followed by a proline-rich region and a C-terminal alpha-helical coiled-coil domain. Northern blot analysis of tissue and cancer cell lines revealed expression of a ubiquitous 3.2-kb transcript as well as of a 2.4-kb transcript in skeletal muscle, kidney, pancreas, and some cancer cell lines. Immunoblot and immunoprecipitation analyses showed expression of an 85-kD protein, larger than the predicted 73 kD, which interacted with CBL.