Kerrick W G, Hoar P E
Ciba Found Symp. 1986;122:183-96. doi: 10.1002/9780470513347.ch11.
Skinned smooth muscle cell bundles were used to study the mechanisms by which Ca2+ and protein phosphorylation regulate smooth muscle contraction. The sarcolemma of skinned cells is rendered permeable to ions and proteins by chemical treatment, allowing the investigator to control the ionic and protein environment within the cells and to determine the effect of this environment on the activation of contraction and protein phosphorylation. Results from these studies show that there is a strong correlation between myosin light chain phosphorylation and force development in skinned smooth muscle cells. Both protein phosphorylation and the activation of tension are affected in the predicted manner by agents known to affect myosin light chain kinase activity. Phosphorylation or thiophosphorylation of myosin light chains in the absence of Ca2+ is sufficient to fully activate contraction in skinned smooth muscle cells. Subsequent dephosphorylation of the myosin light chains by phosphatase results in muscle relaxation. Activation of contraction in skinned smooth muscle cells requires phosphorylation of myosin light chains by the Ca2+- and calmodulin-dependent myosin light chain kinase.
用去皮平滑肌细胞束来研究钙离子和蛋白质磷酸化调节平滑肌收缩的机制。通过化学处理使去皮细胞的肌膜对离子和蛋白质具有通透性，这使研究者能够控制细胞内的离子和蛋白质环境，并确定这种环境对收缩激活和蛋白质磷酸化的影响。这些研究结果表明，在去皮平滑肌细胞中，肌球蛋白轻链磷酸化与力的产生之间存在很强的相关性。已知影响肌球蛋白轻链激酶活性的试剂以预测的方式影响蛋白质磷酸化和张力激活。在没有钙离子的情况下，肌球蛋白轻链的磷酸化或硫代磷酸化足以完全激活去皮平滑肌细胞的收缩。随后磷酸酶使肌球蛋白轻链去磷酸化导致肌肉松弛。去皮平滑肌细胞收缩的激活需要钙离子和钙调蛋白依赖性肌球蛋白轻链激酶对肌球蛋白轻链进行磷酸化。
