Rabbit Anti-Human ZAP70 (phospho Tyr315, Tyr319) monoclonal antibody for FC, ICC, IF, WB. Zeta-associated protein (ZAP-70), a 70 kDa member of the Syk tyrosine kinase family, plays a central role in lymphocyte activation and development, and is implicated in several immune disorders. Upon T-cell antigen receptor. Phosphorylation of both tyrosines 315. Phosphorylation of tyrosines 315 and 319 plays an important role in mediating the positive and negative selection of T cells in thymus. TLR9-activated B-cells display elevated ZAP-70 expression levels which correlate with sustained PKB induction. Additionally,, a major catechin found in green tea, binds directly to ZAP-70 resulting in caspase-mediated apoptosis in Jurkat cells.