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

FEBS Letters

Bartel, Sabine¹  Baltas, Leonidas G¹  Krause, Ernst-Georg¹  Karczewski, Peter¹ 

[1] Max Delbrück Centre for Molecular Medicine (MDC), Robert-Rössle-Straße 10, Berlin 13122, Germany

关键词: Calcium;    Protein kinase;    Catecholamine;    Phospholamban;    Sarcoplasmic reticulum;    Rat heart;    CaM kinase;    Ca2+/calmodulin-dependent protein kinase II;    SRCaM kinase;    endogenous sarcoplasmic reticulum Ca2+/calmodulin-dependent protein kinase;    CaM;    calmodulin;    cAMP;    cyclic AMP;    PKA;    cAMP-dependent protein kinase;    PLB;    phospholamban;    Iso-hearts;    isoproterenol-stimulated hearts;    Iso-SRCaM kinase;    SRCaM kinase from isoproterenol- stimulated hearts;    PVDF;    polyvinylidene difluoride;    PP;    protein phosphatase;   

DOI  :  10.1016/S0014-5793(97)00470-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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.

【 授权许可】

Unknown