[Regulation of intracellular calcium signaling in cardiac muscle].
beta-Adrenoceptor stimulation decreases the calcium-sensitivity of cardiac contractile proteins through cAMP-dependent phosphorylation of troponin I and others. Agents such as alpha 1-adrenergic receptor agonists, endothelin, angiotensin II et al. that stimulate PI turnover elicit positive inotropic responses associated with increase in the calcium-sensitivity. Phorbol ester decreases the apparent sensitivity of the contractile proteins to calcium ion through the phosphorylation of troponin T and others. Myocardial contractile force may be altered by increasing or decreasing the calcium responsiveness of the myofilaments by various drugs, which change the calcium affinity of calcium-binding proteins such as troponin C and calmodulin. Moreover, we isolated a new calcium-binding protein (S100C) from porcine heart and cloned the cDNA for this protein. Modulation of intracellular calcium signaling in cardiac muscle by protein phosphorylation and drugs awaits further investigation.
Tanaka
T
T
Department of Molecular and Cellular Pharmacology, Mie University School of Medicine.
Araki
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000302:isolation & purification; D006321:Heart / Q000502:physiology*; D008969:Molecular Sequence Data; D015398:Signal Transduction / Q000502:physiology*
D002135:Calcium-Binding Proteins; D002118:Calcium