Calmodulin in the regulation of calcium fluxes in cardiac sarcolemma.
Three systems mediate the fluxes of calcium across heart sarcolemma: the slow calcium channel (influx), the ATP-dependent calcium pump (efflux), and the Na+/Ca2+ exchanger (efflux, but possibly also influx). Calmodulin regulates the pumping ATPase by direct interaction and also by activating a protein kinase. The Na+/Ca2+ exchanger is modulated by calmodulin via a phosphorylation-dephosphorylation cycle. Both the kinase and the phosphatase are membrane-bound and calmodulin-sensitive. The kinase has higher Ca2+ affinity than the phosphatase.
Carafoli
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D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism
D002147:Calmodulin; D007473:Ion Channels; D012964:Sodium; D000251:Adenosine Triphosphatases; D002118:Calcium