SH2B2 is an adaptor protein for several members of the tyrosine kinase receptor family and is involved in multiple signalling pathways. It may contribute to coupling from the immunoreceptor to Ras signalling. In collaboration with CBL, it acts as a negative regulator of cytokine signalling. It binds the erythropoietin receptor (EPOR) and suppresses EPO-induced STAT5 activation, possibly by masking STAT5 docking sites in EPOR. It also suppresses PDGF-induced mitogenesis, and it may induce cytoskeletal reorganisation through interaction with VAV3.

The SH2B2 gene encodes a protein that belongs to the SH2B adapter family and contains pleckstrin homology and src homology 2 (SH2) domains. HGNC places it in the pleckstrin homology domain containing, SH2 domain containing and SH2B adaptor protein gene groups, and also lists it among microRNA protein coding host genes. The protein is found in the cytoplasm and at the cell membrane. According to the NCBI Gene summary, it is expressed in B lymphocytes.

In Burkitt's lymphoma cell lines, SH2B2 is tyrosine-phosphorylated in response to B cell receptor stimulation. It binds Shc independently of stimulation and binds Grb2 after stimulation, which suggests a role in signal transduction from the receptor to the Shc/Grb2 pathway. The alias APS is commonly used for this protein in the literature, and mouse and rat both have an orthologous Sh2b2 gene.