Temporal regulation of non-transmembrane protein tyrosine kinase enzyme activity following T cell antigen receptor engagement

• Published in: The Journal of biological chemistry 1994-09, Vol.269 (38), p.23642-23647
• Main Authors: Burkhardt, A L, Stealey, B, Rowley, R B, Mahajan, S, Prendergast, M, Fargnoli, J, Bolen, J B
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Cell Line; Enzyme Activation; Enzyme Precursors - metabolism; Humans; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Lymphocyte Specific Protein Tyrosine Kinase p56(lck); Molecular Sequence Data; Phosphotyrosine; Protein-Tyrosine Kinases - metabolism; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-fyn; Receptors, Antigen, T-Cell - metabolism; Signal Transduction; Syk Kinase; Tyrosine - analogs & derivatives; Tyrosine - metabolism; ZAP-70 Protein-Tyrosine Kinase
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)31563-6

We evaluated in Jurkat T cells the time-dependent responses of Fyn, Lck, Syk, and Zap following antibody-mediated cross-linking of the T cell antigen receptor. Our results show that the protein kinase activities of Fyn and Lck were activated within seconds of receptor cross-linking. Fyn activity, as measured by autophosphorylation and tyrosine phosphorylation of an exogenous substrate, was maximal 5 s to 1 min following receptor cross-linking. Lck was also found to be activated within 5 s of antigen receptor cross-linking but differed from Fyn in that Lck activity was elevated for at least 30 min. Syk and Zap protein kinase activities were found to peak between 5 and 10 min following receptor cross-linking, returning to approximately basal activity levels by 60 min. The protein kinase activities of both Syk and Zap were found to parallel their reactivity in immunoblotting experiments with anti-phosphotyrosine antibodies. Both Syk and Zap were found to associate with the tyrosine-phosphorylated zeta subunit of the T cell antigen receptor. These observations imply that T cell antigen receptor signal transduction involves the activation of multiple members of at least two different families of non-transmembrane protein tyrosine kinases.