PROTEIN-KINASE-C ENHANCES MYOSIN LIGHT-CHAIN KINASE EFFECTS ON FORCE DEVELOPMENT AND ATPASE ACTIVITY IN RAT SINGLE SKINNED CARDIAC-CELLS
PROTEIN-KINASE-C ENHANCES MYOSIN LIGHT-CHAIN KINASE EFFECTS ON FORCE DEVELOPMENT AND ATPASE ACTIVITY IN RAT SINGLE SKINNED CARDIAC-CELLS
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DOI：
10.1042/bj2850311
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发表时间：
1992-07-01
影响因子：
4.1
通讯作者：
VASSORT, G
中科院分区：
文献类型：
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作者：
CLEMENT, O;PUCEAT, M;VASSORT, G
许多神经激素通过细胞内Ca 2+浓度的变化来改变心脏收缩力。相反，α-1-肾上腺素能和毒蕈碱刺激改变了收缩蛋白对Ca 2+离子的敏感性。本研究通过测量大鼠单个皮肤心肌细胞产生的力，证明了Ca 2 +-钙调蛋白-肌球蛋白轻链激酶（MLCK）复合物诱导这些容易接近的肌丝的Ca 2+敏感性（0.14 pCa单位）大幅增加。当蛋白激酶C（PKC）与MLCK一起加入时，这种增加进一步增强高达0.19 pCa单位。类似地，在MLCK的存在下以及在两种激酶的存在下，悬浮液中的皮肤细胞的Ca 2 + ATP酶活性增加。P-32标记和SDS/PAGE显示，这些变化与轻链2（LC 2）磷酸化以及加入PKC时肌钙蛋白I和肌钙蛋白T的磷酸化有关。虽然在较小的程度上比平滑肌，心肌肌球蛋白LC 2的磷酸化可能参与心脏收缩力的调制。
Many neurohormones alter the force of cardiac contraction by variations in the intracellular Ca2+ concentration. alpha-1-Adrenergic and muscarinic stimulations, rather, modify the sensitivity of contractile proteins to Ca2+ ions. Measuring the force developed by rat single skinned cardiac cells, the present study demonstrates that the Ca2+-calmodulin-myosin light-chain kinase (MLCK) complex induces a large increase in Ca2+ sensitivity (0.14 pCa unit) of these easily accessible myofilaments. This increase is further enhanced by up to 0.19 pCa unit when protein kinase C (PKC) is added together with MLCK. Similarly, the Ca2+ ATPase activity of skinned cells in suspension is increased in the presence of MLCK and further in the presence of both kinases. P-32-labelling and SDS/PAGE show that these changes are associated with light-chain 2 (LC2) phosphorylation together with phosphorylation of troponin I and troponin T when PKC is added. Although to a smaller extent than in smooth muscle, phosphorylation of cardiac myosin LC2 may be involved in the modulation of heart contractility.