Calcium, Calmodulin, and Insulin Action in the Adipocyte
The cellular mechanism of insulin action remains enigmatic despite intensive research efforts. Over the past 20 years, considerable effort has focused on the signal transduction mechanisms that are responsible for linking the primary signal (insulin binding to its specific receptor on the cell surface) to the characteristic multicomponent pleiotypic cellular response (for re views, see Czech, 1977, 1985). Although considerable evidence supports the concept that the final common pathway by which insulin regulates a variety of intracellular target pathways is the phosphorylation and dephosphorylation of key intracellular target proteins, the signal transduction processes remain unknown. Clearly, the complexity of the metabolic responses of the cell to insulin accompanied by our increasing knowledge about intracellular signals and mediators lend considerable support to the contention that the signal transduction process for insulin most assuredly involves multiple “mediator” pathways acting in a coordinated, orchestrated manner rather than a single mediator or messenger.
KeywordsTyrosine Sarcoma Verapamil Glucagon EGTA
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