Redox regulation of a src family protein tyrosine kinase p56lck in T cells
Nakamura, K.; Hori, T.; Sato, N.; Sugie, K.; Kawakami, T.; Yodoi, J.
Oncogene 8(11): 3133-3139
1993
ISSN/ISBN: 0950-9232 PMID: 8414515 Document Number: 410465
Protein tyrosine phosphorylation was examined after T cells were exposed to oxidative stress in vitro to investigate the possible involvement of redox regulation in T-cell signaling. Oxidative reagents such as hydrogen peroxide (H-2O-2) and diamide, which oxidize the free sulfhydryl groups in the cells, markedly induced tyrosine phosphorylation of multiple cellular proteins, especially a 55-kDa protein, of cultured peripheral blood T lymphocytes (PBL blasts). The 55-kDa molecule phosphorylated by diamide turned out to be a src family protein tyrosine kinase, p56-lck. The immune complex kinase assay showed that the kinase activity of p56-lck of diamide-treated PBL blasts was enhanced. The tryptic peptide mapping of p56-lck demonstrated that diamide induced the phosphorylation both at Tyr-394 (autophosphorylation site) and at Tyr-505 (negative regulatory site). Taken together, the tyrosine phosphorylation and presumably kinase activity of p56-lck were swiftly enhanced by oxidative stress, indicating that T cells have a redox-sensitive signaling mechanism, which is partly mediated by the lymphocyte-specific protein tyrosine kinase p56-lck.