Syk Recombinant Rabbit mAb (S-4400-11)

Syk (spleen tyrosine kinase) is a non-receptor tyrosine kinase widely expressed in hematopoietic cells, belonging to the Syk family. Its structural features include two tandem SH2 domains at the N-terminus, which recognize and bind to dual-phosphorylated tyrosine residues within immunoreceptor tyrosine-based activation motifs (ITAMs), thereby mediating its own activation and initiating downstream signaling cascades. It plays a central role in signal transduction through various immune receptors, including the B-cell receptor (BCR), T-cell receptor (TCR), and Fc receptors. By phosphorylating downstream substrates such as BLNK, SLP-76, and VAV, it regulates key immune responses including lymphocyte activation, proliferation, differentiation, and antibody production. Beyond adaptive immunity, Syk also participates in innate immune responses mediated by receptors such as FcγR and Dectin-1 in macrophages, neutrophils, dendritic cells, and mast cells, and plays a role in platelet adhesion and aggregation. Given its central position in immune signaling pathways, Syk dysfunction is associated with various diseases—its hyperactivation can drive allergic diseases, autoimmune disorders (such as rheumatoid arthritis and systemic lupus erythematosus), and B-cell lymphomas. Syk inhibitors (such as fostamatinib) have already been used clinically to treat immune thrombocytopenia and show promising applications in various inflammatory and oncological conditions.