The endogenous cardiac sarcoplasmic reticulum Ca2+/calmodulin‐dependent kinase is activated in response to β‐adrenergic stimulation and becomes Ca2+‐independent in intact beating hearts
Open Access
- 9 June 1997
- journal article
- Published by Wiley in FEBS Letters
- Vol. 409 (2) , 131-136
- https://doi.org/10.1016/s0014-5793(97)00470-5
Abstract
We investigated the effects of β‐adrenergic stimulation on the activity of the endogenous cardiac sarcoplasmic reticulum Ca2+/calmodulin‐dependent protein kinase (SRCaM kinase) in Langendorff‐perfused rat hearts. We found that isoproterenol induced generation of autonomous (Ca2+‐independent) SRCaM kinase activity to 28±4.4% of the total activity. Moreover, dephosphorylation of the autonomous SRCaM kinase with protein phosphatase 2A resulted in an enzyme that was again dependent on Ca2+ and calmodulin for its activity. Activation of SRCaM kinase was coupled to phospholamban phosphorylation and activation of the cAMP‐signaling system. Our results suggest that the cardiac SRCaM kinase is activated in response to β‐adrenoceptor stimulation. This activation stimulates autophosphorylation at its regulatory domain and converts it to an active Ca2+‐independent species that may be the basis for potentiation of Ca2+ transients in the heart.Keywords
This publication has 32 references indexed in Scilit:
- Evidence that autophosphorylation at Thr-286/Thr-287 is required for full activation of calmodulin-dependent protein kinase IIBiochimica et Biophysica Acta (BBA) - Molecular Cell Research, 1996
- In Situ Ca2+ Dependence for Activation of Ca2+/Calmodulin- dependent Protein Kinase II in Vascular Smooth Muscle CellsJournal of Biological Chemistry, 1996
- The cardiac sarcoplasmic reticulum phospholamban kinase is a distinct δ‐CaM kinase isozymeFEBS Letters, 1995
- Regulation of phospholamban and troponin-I phosphorylation in the intact rat cardiomyocytes by adrenergic and cholinergic stimuli: roles of cyclic nucleotides, calcium, protein kinases and phosphatases and depolarizationMolecular and Cellular Biochemistry, 1995
- Activation of calcium and calmodulin dependent protein kinase II during stimulation of insulin secretionCell Calcium, 1994
- Phosphorylation of the L‐type calcium channel β subunit is involved in β‐adrenergic signal transduction in canine myocardiumFEBS Letters, 1993
- Protein phosphorylation and cardiac function: cholinergic-adrenergic interactionCardiovascular Research, 1993
- Role of Ca2+-calmodulin dependent phospholamban phosphorylation on the relaxant effect of ?-adrenergic agonistsMolecular and Cellular Biochemistry, 1993
- Identification of the major protein phosphatases in mammalian cardiac muscle which dephosphorylate phospholambanEuropean Journal of Biochemistry, 1991
- Purification and characterization of a calcium-calmodulin-dependent phospholamban kinase from canine myocardiumBiochemistry, 1989