T Cell Antigen Receptor: Biochemical Aspects of Signal Transduction.(Reannouncement with New Availability Information)

摘要

As of 1984 there had been many examples of ligand-induced receptorphosphorylation. For example, serine phosphorylation of the beta-adrenergic receptor induced by ligand had been demonstrated and related to receptor desensitization. Tyrosine phosphorylation of the epidermal growth factor (EGF) receptor and insulin receptors had been shown to be correlated with ligand binding and receptor kinase activation. In view of these studies pointing to the central role of protein kinase activation in receptor-induced signal transduction, we asked whether the T cell antigen receptor was phosphorylated upon antireceptor engagement. To summarize several studies we demonstrated that upon the addition of antigen, antireceptor antibody, or stimulatory anti-Thy-l antibody, the antigen receptor is rapidly phosphorylated on two subunits. The CD3 gamma chain is phosphorylated on serine residues. While the T cell receptor zeta chain is phosphorylated on tyrosine residues. The antigen-induced serine phosphorylation can be mimicked by addition of phorbol ester and is dependent on the presence of protein kinase C.