SH2B2 siRNA – SH2B Adapter Protein 2 (Human)

The protein encoded by this gene is expressed in B lymphocytes and contains pleckstrin homology and src homology 2 (SH2) domains. In Burkitt's 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 the Shc/Grb2 pathway. [provided by RefSeq, Jun 2009]

APS: an adapter protein involved in coupling immunoreceptors to Ras signaling. Acts as a negative regulator of cytokine signaling in collaboration with CBL. Binds to EPOR and suppresses EPO-induced STAT5 activation, possibly through a masking effect on STAT5 docking sites in EPOR. Suppresses PDGF-induced mitogenesis. Interacts with several proteins including KIT/c-KIT, SHC, GRB2, EPOR, CBL/c-CBL, PDGFR, VAV1 and VAV3. Interacts with SHC through its N-terminal region, with GRB2 via the phosphorylated C-terminus and with EPOR and KIT via its SH2 domain. Interacts with GRB2 after B-cell antigen receptor stimulation. Interacts with VAV3 via its PH domain, inducing cytoskeletal reorganization. Expressed in spleen, prostrate, testis, uterus, small intestine and skeletal muscle. Among haematopoietic cell lines, expressed exclusively in B-cells. Not expressed in most tumor cell lines. Tyrosine phosphorylated by JAK2, KIT and other kinases activated by B-cell receptor in response to stimulation with cytokines, IL3, IL5, PDGF, IGF1, IGF2, CSF2/GM-CSF and cross-linking of the B-cell receptor complex.

Protein type: Adaptor/scaffold

Chromosomal Location of Human Ortholog: 7q22

Cellular Component: ruffle; cytoplasm; plasma membrane; stress fiber; actin filament; cytosol

Molecular Function: identical protein binding; protein binding; signal transducer activity; SH3/SH2 adaptor activity; JAK pathway signal transduction adaptor activity; transmembrane receptor protein tyrosine kinase adaptor protein activity

Biological Process: antigen receptor-mediated signaling pathway; regulation of Ras protein signal transduction; nervous system development; positive regulation of signal transduction; cytokine and chemokine mediated signaling pathway; B-1 B cell homeostasis; signal transduction; regulation of JAK-STAT cascade; insulin receptor signaling pathway; brown fat cell differentiation; regulation of metabolic process; blood coagulation; actin cytoskeleton organization and biogenesis