CYTOKINE SIGNAL-TRANSDUCTION

The normal growth, maturation, and activation of cells in most tissues requires stimulation with a defined set of growth factors. These grow th factors bind cognate receptors on surface of target cells, and stim ulate specific intracellular signals. Many of these signals culminate in the induction of a ligand-specific set of genes. The characterizati on of signaling components that mediate the induction of genes in resp onse to IFNs has led to the identification of a new signal transductio n pathway. The components of this pathway are able to rapidly transduc e high fidelity signals directly from the receptor to the nucleus. Rec ently, many other cytokines and growth factors, including IFN-alpha, I FN-gamma, IL-6, and prolactin (PRL), have been shown to induce new gen es through the same signaling paradigm.