Open Accessp56lck-independent activation and tyrosine phosphorylation of p72syk by T-cell antigen receptor/CD3 stimulation.
Author(s) -
Clément Couture,
Gottfried Baier,
Am Altman,
Tomas Mustelin
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.12.5301
Subject(s) - t cell receptor , phosphorylation , proto oncogene tyrosine protein kinase src , tyrosine phosphorylation , tyrosine kinase , biology , cd3 , microbiology and biotechnology , tyrosine , src family kinase , receptor tyrosine kinase , tyrosine protein kinase csk , t cell , sh2 domain , signal transduction , antigen , biochemistry , cd8 , immune system , immunology
Activation of resting T lymphocytes by ligands to the T-cell antigen receptor (TCR)/CD3 complex is initiated by rapid tyrosine phosphorylation of cellular proteins. Protein-tyrosine kinases (PTKs) of the src family are known to be important, but the mechanism of their recruitment and their interactions with PTKs of other families are incompletely understood. We show that a member of another family of PTKs, the p72syk kinase, is constitutively bound to the TCR/CD3 complex and becomes tyrosine phosphorylated and activated within 1 min after TCR/CD3 stimulation. This activation did not depend on the presence of p56lck in T cells and in transfected COS cells. In both cases, however, the phosphorylation of cellular substrates was augmented by src family PTKs. We propose that p72syk may act as an immediate receptor-activated kinase upstream of the related p70zap PTK and the src family PTKs p56lck and p59fyn in T cells and that these src family PTKs act as signal amplifiers.