CAS BI 203 Lecture Notes - Lecture 22: Cytokine Receptor, Eif2, Eif2B
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Answer: pka regulates many transcription factor (tfs) directly. First messenger: ligand that binds to the receptor to start the cascade. Second messenger: camp: a small intracellular molecule, that is altered (chemical or localization) in response to activation of a cell surface receptor, whose alteration further transduces a signal. Creb binds to cre in the nucleus. (start in cytosol) elevated camp levels activation of protein kinase a (pka) pka enters the nucleus phosphorylation of creb recruitment of coactivator activation of transcription. Many genes targeted by creb are involved in regulating cell proliferation, survival, and differentiation. Protein phosphorylation is rapidly reversed by protein phosphatases, which terminate responses initiated by receptor activation of protein kinases. Cyclic gmp (cgmp) is another important second messenger. cgmp is formed from gtp by guanylyl cyclases and degraded to gmp by a phosphodiesterase. cgmp mediates biological responses, such as blood vessel dilation. In the vertebrate eye, cgmp is the second messenger that converts visual signals to nerve impulses.