HLSC 3P19 Study Guide - Quiz Guide: Excitatory Postsynaptic Potential, Endoplasmic Reticulum, Calcium Signaling
15 Dec 2019
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Document Summary
Almost all second messenger signaling involves reversible phosphorylation, which performs two principal functions in signaling: amplification and flexible regulation. Dephosphorylation erases the memory, taking a longer time to do so than is required for dissociation of an allosteric ligand. In flexible regulation, differing substrate specificities of the multiple protein kinases regulated by second messengers provide branch points in signaling pathways that may be independently regulated. In this way, camp, ca2+, or other second messengers can use the presence or absence of particular kinases or kinase substrates to produce quite different effects in different cell types. The existence of a specific drug receptor is usually inferred from studying the structure-activity relationship of a group of structurally similar congeners of the drug that mimic or antagonize its effects. Thus, if a series of related agonists exhibits identical relative potencies in producing two distinct effects, it is likely that the two effects are mediated by similar or identical receptor molecules.
