Signal-transducing adaptor protein 2 (STAP2)

Signal-transducing adaptor protein 2 (STAP2) is a multifunctional intracellular adaptor protein that lacks intrinsic catalytic activity but mediates protein-protein interactions in various signal transduction pathways. It contains a pleckstrin homology (PH) domain at the N-terminus, a central Src homology 2 (SH2)-like domain, and a C-terminal proline-rich region with a YXXQ motif, important for binding proteins like STAT3. STAP2 is expressed in many tissues and cell types and regulates both adaptive and innate immune responses by connecting cell surface receptors (such as cytokine receptors, FcεRI, T-cell receptor, Toll-like receptor 4, c-Fms receptor) to downstream signaling molecules like STAT3, STAT5, MyD88, IKKβ, and others. It influences T-cell proliferation, differentiation, migration, and apoptosis, modulates B-cell and myeloid cell recovery/stress responses, supports memory CD8+ T cell maintenance, and is also implicated in cancer cell migration, proliferation, and resistance to certain tyrosine kinase inhibitors. As a signaling hub, dysregulation of STAP2 has been linked to inflammatory diseases and cancer progression, making it of potential therapeutic interest, though there are no known drugs that specifically target STAP2 directly at present.

Other names

STAP2BKSBRK substratebreast tumor kinase substrateBrk kinase substrate