Protein kinase C enhances myosin light-chain kinase effects on force development and ATPase activity in rat single skinned cardiac cells

摘要: Many neurohormones alter the force of cardiac contraction by variations in intracellular Ca2+ concentration. alpha 1-Adrenergic and muscarinic stimulations, rather, modify sensitivity contractile proteins to Ca(2+)-calmodulin-myosin light-chain kinase (MLCK) complex induces a large increase (0.14 pCa unit) these easily accessible myofilaments. This is further enhanced up 0.19 unit when protein C (PKC) added together with MLCK. Similarly, ATPase activity skinned cells suspension increased presence MLCK both kinases. 32P-labelling SDS/PAGE show that changes are associated 2 (LC2) phosphorylation troponin I T PKC added. Although smaller extent than smooth muscle, myosin LC2 may be involved modulation heart contractility.