A COMMON NUCLEAR SIGNAL-TRANSDUCTION PATHWAY ACTIVATED BY GROWTH-FACTOR AND CYTOKINE RECEPTORS

Growth factors and cytokines act through cell surface receptors with different biochemical properties. Yet each type of receptor can elicit similar as well as distinct biological responses in target cells, suggesting that distinct classes of receptors activate common gene sets. Epidermal growth factor, interferon-gamma interleukin-6 all activated, through direct tyrosine phosphorylation, latent cytoplasmic transcription factors that recognized similar DNA elements. However, different ligands activated different patterns of factors with distinct DNA-binding specificities in the same and in different cells. Thus, unrelated receptors may activate a common nuclear signal transduction pathway that, through differential use of latent cytoplasmic proteins, permits these receptors to regulate both common and unique sets of genes.