ZAP 70 (Zeta-chain (TCR) Associated Protein Kinase 70kDa, ZAP70, ZAP-70, 70kD Zeta-associated Protein, FLJ17670, FLJ17679, Syk-related Tyrosine Kinase, SRK, STD, Tyrosine-protein Kinase ZAP-70, TZK)

The ZAP-70 (zeta-associated protein of 70kD) tyrosine kinase was identified as a tyrosine phosphoprotein that associates with TCR zeta subunit and undergoes tyrosine phosphorylation following TCR stimulation. ZAP-70 is a Syk family tyrosine kinase primarily expressed in T and NK cells that plays an essential role in signaling through the TCR. TCR-mediated activation of T cells is crucial to the immune response. In humans, ZAP-70 gene mutations resulting in lower ZAP-70 protein expression levels or expression of catalytically inactive ZAP-70 proteins, have been identified. ZAP-70 deficiency results in the absence of mature CD8+ T cells and the prevention of TCR-mediated activation of CD4+ T cells, and it can lead to severe combined immunodeficiency. ZAP-70 is cytosolic protein migrating at 70kD in SDS-PAGE. It contains two N-terminal SH2 domains (Src homology domain 2) and a C-terminal kinase domain. Crystal structure of the ZAP-70 SH2 domains in complex with a TCR zeta subunit peptide was described. During T cell activation , the binding of ZAP-70 SH2 domains to the phosphorylated zeta subunit on the activated TCR complex causes a colocalization with the Lck tyrosine kinase that phosphorylates ZAP-70 on Tyr493 in the activation loop. ZAP-70 autophosphorylates multiple tyrosines in the region between the SH2 domains and the kinase domain, including the binding sites for additional SH2-containing signaling proteins such as SLP-76, LAT, Lck, PLCgamma1, Vav, Shc, Ras-GAP, and Abl. ZAP-70-mediated activation of these downstream effectors leads to the release of intracellular calcium stores, and the transcription of interleukin-2 and other genes important for an immune response. Gene location: human chromosome 2q12. Applications: Suitable for use in Western Blot. Other applications not tested. Recommended Dilution: Western Blot: 1:1000 Optimal dilutions to be determined by the researcher. Positive Control: Jurkat T cell line Storage and Stability: May be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.