Phospho-Zap70 (Tyr319)/Syk (Tyr352) (A3) rabbit mAb APC conjugate

ZAP70 (Tyrosine-protein kinase ZAP-70, phospho Zap70) is a protein tyrosine kinase (PTK) that associates with the z subunit of the T cell antigen receptor (TCR) and undergoes tyrosine phosphorylation following TCR stimulation (1,2). Following TCR engagement, Zap70 is rapidly phosphorylated on several tyrosine residues through autophosphorylation and transphosphorylation by the Src family tyrosine kinase Lck (3,4). ZAP70 contains two SH2-like domains with the PTK domain located at the C-terminus (5). It appears that both phospho Zap70 and Syk are recruited to the phosphorylated CD3 and z subunits after TCR stimulation (5). Phosphorylation of Tyr319 is required for the assembly of a phospho Zap70-containing signaling complex that leads to the activation of the PLC-gamma1-dependent and Ras-dependent signaling cascades in antigen-stimulated T cells. The orthologous Tyr352 residue in Syk is also involved in the association with PLC-gamma1 (6,7).