SIGNALING PATHWAYS ACTIVATED BY PROTEIN-TYROSINE PHOSPHORYLATION IN LYMPHOCYTES

Antigen and cytokine receptors induce rapid tyrosine phosphorylation o f receptor subunits, other membrane proteins, and signaling components . Each receptor induces phosphorylation of a number of proteins. Altho ugh there is often overlap between targets of different receptors, any given receptor only induces phosphorylation of a subset of possible t argets. How this choice of targets is achieved for these receptors is not yet understood. The cellular events downstream of some signaling c omponents are beginning to come into view. Recent progress in these ar eas is discussed.