Regulation of contraction by myosin phosphorylation. A comparison between smooth and skeletal muscles.
Regulation of contraction by myosin phosphorylation. A comparison between smooth and skeletal muscles.
复制标题
通过肌球蛋白磷酸化调节收缩。
DOI：
10.1016/0006-2952(80)90063-5
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发表时间：
1980
影响因子：
5.8
通讯作者：
Cooke,R
中科院分区：
文献类型：
--
作者：
Stull,JT;Blumenthal,DK;Cooke,R
酶的磷酸化和去磷酸化已被认为是调节许多代谢过程的生化机制[L-5]。最近，有研究表明，特定的肌原纤维蛋白也被蛋白激酶磷酸化，在某些情况下，收缩过程可能通过蛋白磷酸化来调节[6]。这篇评论将集中在肌球蛋白轻链激酶这种钙离子依赖的酶对肌球蛋白的磷酸化特性。尽管骨骼肌和平滑肌有几个共同的一般特征，但也有重要的区别，这可能部分解释了这两种不同类型的肌肉的不同生理特性和药理反应。在所有类型的肌肉中，钙离子释放到肌浆中是兴奋-收缩偶联的主要事件。随后，钙离子结合到与收缩装置相关或作用于收缩装置的蛋白质上特定的高亲和力部位，最终导致收缩。虽然所有类型肌肉的收缩都是收缩蛋白肌动蛋白和肌球蛋白相互作用的结果，但在平滑肌肉和骨骼肌中，钙离子触发肌动球蛋白相互作用的机制明显不同。肌球蛋白相互作用调控的这些差异可以归因于肌球蛋白分子同工酶的不同以及调节钙离子作用的调节蛋白的不同。肌球蛋白是由两个高分子量重链亚基和四个低分子量轻链亚基组成的六聚体分子。天然肌球蛋白的整体构型是一个卷曲的尾部区域和两个突出的随机卷曲头部区域。分子的尾部区域与其他肌球蛋白分子的尾部区域相互作用，形成粗大的细丝。头部区域从粗丝突起，与肌动蛋白的细丝(细丝)结合。肌肉的滑动细丝理论
Phosphorylation and dephosphorylation of enzymes have been recognized as biochemical mechanisms by which many metabolic processes are regulated [l-5]. Recently, it was shown that specific myofibrillar proteins are also phosphorylated by protein kinases and that in some cases the contractile process may be regulated via protein phosphorylation [6]. This commentary will focus on the properties of phosphorylation of myosin by the Ca’+-dependent enzyme, myosin light chain kinase. Although there are several general features that are shared by skeletal and smooth muscles, there are also important distinctions thay may explain, in part, the diverse physiological properties and pharmacological responses of these two different types of muscles. The release of Ca2’into the sarcoplasm is the primary event in excitation-contraction coupling in all types of muscle. The subsequent binding of Ca*+ to specific high-affinity sites on proteins associated with, or acting on, the contractile apparatus ultimately results in contraction. Although contraction in all types of muscle results from the interaction of the contractile proteins actin and myosin, the mechanism by which Ca*+ triggers actomyosin interactions is markedly different in smooth and skeletal muscles. These differences in regulation of actomyosin interactions can be ascribed to isozymic differences in the myosin molecule and to differences in the regulatory proteins which mediate the effects of Ca2+. Myosin is a hexameric molecule composed of two high molecular weight heavy chain subunits and four low molecular weight light chain subunits. The overall configuration of native myosin is that of a coiledcoil tail region and two protruding random coil head regions. The tail region of the molecule interacts with the tail regions of other myosin molecules to form thick filaments. The head regions project from the thick filaments to bind to filaments of actin (the thin filaments). The sliding filament theory of muscle