Tyrosine phosphorylation of the human T cell antigen receptor zeta-chain: activation via CD3 but not CD2 |
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| Authors: | A M Weissman P Ross E T Luong P Garcia-Morales M L Jelachich W E Biddison R D Klausner L E Samelson |
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| Institution: | Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, Bethesda, MD 20892. |
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| Abstract: | TCR stimulation by Ag or anti-receptor antibodies in murine T cells results in the activation of two independent protein kinases, protein kinase C (PKC) and a protein tyrosine kinase. Similarly, stimulation of murine Thy-1 or Ly-6 with mAb also results in activation of both of these kinase pathways. Tyrosine phosphorylation in all cases occurs on the TCR zeta-chain. It is known that Ag and anti-receptor antibodies activate PKC in human T cells. In this study we demonstrate that mitogen or anti-CD3 antibodies activate tyrosine phosphorylation of the human TCR-zeta-chain. PMA, which activates PKC, does not result in zeta-chain tyrosine phosphorylation. Stimulation of human T cells by antibodies that bind the CD2 molecule is an alternate mode of inducing T cell proliferation. These antibodies surprisingly do not induce tyrosine phosphorylation of the zeta-chain. Thus, different methods of cellular activation can result in distinguishable patterns of receptor-mediated biochemical signaling events. |
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