Broschat K O, Stidwill R P, Burgess D R
Cell. 1983 Dec;35(2 Pt 1):561-71. doi: 10.1016/0092-8674(83)90190-3.
The intestinal epithelial cell brush border (BB) is a useful model for nonmuscle cell motility. We studied regulation of BB motility by analyzing myosin phosphorylation and its association with the cytoskeleton. Our results demonstrate that myosin associates with the cytoskeleton only when it is dephosphorylated. Myosin light chain kinase substrates release myosin, phosphorylated and in the form of filaments, from the cytoskeleton. Although ITP and GTP serve as myosin ATPase substrates, they do not cause BB contraction, myosin release, or phosphorylation. Brush border contraction occurs with ATP or with a mixture of ITP and ATP gamma S. Therefore, phosphorylation regulates myosin association with the cytoskeleton, myosin is not bound at the actin-myosin binding site, and when phosphorylated, myosin forms filaments for movement.
肠上皮细胞刷状缘（BB）是研究非肌肉细胞运动的有用模型。我们通过分析肌球蛋白磷酸化及其与细胞骨架的关联来研究BB运动的调节机制。我们的研究结果表明，肌球蛋白只有在去磷酸化状态下才会与细胞骨架结合。肌球蛋白轻链激酶底物会使磷酸化的丝状肌球蛋白从细胞骨架上释放出来。虽然肌醇三磷酸（ITP）和鸟苷三磷酸（GTP）可作为肌球蛋白ATP酶的底物，但它们不会引起BB收缩、肌球蛋白释放或磷酸化。刷状缘收缩是由ATP或ITP与ATPγS的混合物引起的。因此，磷酸化作用调节肌球蛋白与细胞骨架的结合，肌球蛋白并非结合在肌动蛋白-肌球蛋白结合位点上，并且磷酸化时，肌球蛋白会形成用于运动的丝状结构。
