In adipocytes, insulin stimulates glucose transport primarily by promoting the translocation of GLUT4 to the plasma membrane. Requirements for Ca(2+)/calmodulin during insulin-stimulated GLUT4 translocation have been demonstrated; however, the mechanism of action of Ca(2+) in this process is unknown. Recently, myosin II, whose function in non-muscle cells is primarily regulated by phosphorylation of its regulatory light chain by the Ca(2+)/calmodulin-dependent myosin light chain kinase (MLCK), was implicated in insulin-stimulated GLUT4 translocation. The present studies in 3T3-F442A adipocytes demonstrate the novel finding that insulin significantly increases phosphorylation of the myosin II RLC in a Ca(2+)-dependent manner. In addition, ML-7, a selective inhibitor of MLCK, as well as inhibitors of myosin II, such as blebbistatin and 2,3-butanedione monoxime, block insulin-stimulated GLUT4 translocation and subsequent glucose transport. Our studies suggest that MLCK may be a regulatory target of Ca(2+)/calmodulin and may play an important role in insulin-stimulated glucose transport in adipocytes.

中文翻译：

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肌球蛋白II调节轻链的磷酸化在3T3-F442A脂肪细胞中胰岛素刺激的GLUT4易位中的意义。

在脂肪细胞中，胰岛素主要通过促进GLUT4向质膜的转运来刺激葡萄糖转运。已经证明了在胰岛素刺激的GLUT4易位过程中Ca（2 +）/钙调蛋白的需求；但是，Ca（2+）在此过程中的作用机理尚不清楚。最近，肌球蛋白II，其在非肌肉细胞中的功能主要是由其调节轻链的磷酸化，由Ca（2 +）/钙调蛋白依赖性肌球蛋白轻链激酶（MLCK）来调节的，与胰岛素刺激的GLUT4易位有关。目前在3T3-F442A脂肪细胞中的研究表明了新发现，即胰岛素以Ca（2+）依赖性方式显着增加了肌球蛋白II RLC的磷酸化。此外，ML-7的选择性抑制剂ML-7以及肌球蛋白II的抑制剂（如抑菌素和 3-丁二酮单肟，阻断胰岛素刺激的GLUT4易位和随后的葡萄糖转运。我们的研究表明，MLCK可能是Ca（2 +）/钙调蛋白的调控靶标，并且可能在胰岛素刺激的脂肪细胞葡萄糖转运中起重要作用。