MYOSIN LINKED CALCIUM REGULATION IN VERTEBRATE SMOOTH-MUSCLE
MYOSIN LINKED CALCIUM REGULATION IN VERTEBRATE SMOOTH-MUSCLE
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DOI：
10.1038/252405a0
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发表时间：
1974-01-01
期刊：
影响因子：
64.8
通讯作者：
BREMEL, RD
中科院分区：
文献类型：
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作者：
BREMEL, RD
肌动蛋白和肌球蛋白丝相互作用产生的收缩性通常由钙离子浓度控制。原则上，钙离子对这种相互作用的调节可以在肌动蛋白或肌凝蛋白丝的水平上进行，这两种类型的调节系统都存在于自然界中。在脊椎动物骨骼肌中，肌钙蛋白是钙受体，附着在肌动蛋白丝上。肌钙蛋白的作用是抑制性的：当没有钙离子与肌动蛋白结合时，肌动蛋白和肌凝蛋白之间的相互作用被阻止1 - 4。这种抑制被解除，相互作用发生在钙浓度足以占据分子上的钙结合位点时。第二种调节系统是在软体动物肌肉中发现的，也存在于其他缺乏肌钙蛋白5,6的无脊椎动物系统中。在某些情况下，这两种类型的调节似乎出现在同一块肌肉中。在这里，我提出的证据表明，这种肌球蛋白相关的调节系统不仅限于无脊椎动物，而且也存在于高等脊椎动物的平滑肌中。关于这种肌肉类型的调节系统的更详细的描述在其他地方提出8,9。
CONTRACTILITY resulting from the interaction of actin and myosin filaments is in general controlled by the concentration of calcium ions. The regulation of this interaction by Ca ions can, in principle, be exercised at the level either of the actin or of the myosin filaments and both these types of regulatory system are found in nature. In vertebrate skeletal muscle troponin is the Ca receptor and is attached to the actin filament. The action of troponin is inhibitory: when no Ca ions are bound to it the interaction between actin and myosin is prevented1–4. This inhibition is relieved and interaction occurs at calcium concentrations sufficient for the Ca binding sites on the molecule to be occupied. The second type of regulatory system was discovered in molluscan muscles and is present in other invertebrate systems which lack troponin5,6. In some cases both types of regulation seem to be present in the same muscle6,7. Here I present evidence which shows that such a myosin-linked regulatory system is not confined to invertebrates but is also present in smooth muscles of higher vertebrates. A more detailed description of the regulatory system in this muscle type is presented elsewhere8,9.