SH2B Adaptor Protein 2 (SH2B2)

SH2B2 is expressed in B lymphocytes and contains pleckstrin homology and src homology 2 (SH2) domains. In Burkitt lymphoma cell lines, it is tyrosine phosphorylated in response to B cell receptor stimulation. Because it binds Shc independent of stimulation and Grb2 after stimulation, it appears to play a role in signal transduction from the receptor to Shc/Grb2. The deduced 632-amino acid APS adaptor protein contains a pleckstrin homology (PH) domain, an Src homology 2 (SH2) domain, and a C-terminal tyrosine phosphorylation site. APS is structurally similar to the T-cell adaptor protein/signal transducer LNK. Immunoprecipitation analysis indicated that APS associates with SHC regardless of BCR stimulation and with GRB2 only after BCR stimulation.