Rho-associated kinase directly induces smooth muscle contraction through myosin light chain phosphorylation
Rho-associated kinase directly induces smooth muscle contraction through myosin light chain phosphorylation
复制标题
DOI：
10.1074/jbc.272.19.12257
复制
发表时间：
1997-05-09
影响因子：
4.8
通讯作者：
Ito, M
中科院分区：
文献类型：
--
作者：
Kureishi, Y;Kobayashi, S;Ito, M
小GTdR Rho在平滑肌的Ca 2+增敏中起关键作用。然而，由于重要的可扩散辅因子的损失，在广泛的Triton X-100透化的平滑肌制备物中，GTP结合的Rho活性形式未能发挥Ca 2+敏化作用（Gong，M. C.的方法，饭冢，K.，尼克松，G.，布朗，J. P.，霍尔，A.，埃克莱斯顿，J.F.，Sugai，M.，小林，Somlyo，A.五、和Somlyo，A. P.（1996）Proc. Natl. Acad. Sci. U.S.A.93，1340-1345），在此我们证明了Rho相关激酶的收缩作用（Rho-激酶），最近被确定为Rho的假定靶点，在Triton X-100透化的兔门静脉平滑肌上，Rho-激酶的组成型活性形式引入Triton X-100的胞质溶胶中-透化平滑肌引起收缩和肌球蛋白轻链的单磷酸化水平的成比例增加，在存在和不存在胞质Ca 2+。组成型活性Rho激酶的这些作用对渥曼青霉素（一种有效的肌球蛋白轻链激酶抑制剂）不敏感。免疫印迹分析表明，天然Rho激酶的量显着低于Triton X-100透化组织比在完整的组织。我们的研究结果表明，Rho-激酶直接调节平滑肌收缩，通过肌球蛋白轻链磷酸化，独立的钙离子-钙调蛋白依赖性肌球蛋白轻链激酶途径。
Small GTPase Rho plays pivotal roles in the Ca2+ sensitization of smooth muscle. However, the GTP-bound active form of Rho failed to exert Ca2+-sensitizing effects in extensively Triton X-100-permeabilized smooth muscle preparations, due to the loss of the important diffusible cofactor (Gong, M. C., Iizuka, K., Nixon, G., Browne, J. P., Hall, A., Eccleston, J. F., Sugai, M., Kobayashi, S., Somlyo, A. V., and Somlyo, A. P. (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 1340-1345), Here we demonstrate the contractile effects of Rho-associated kinase (Rho-kinase), recently identified as a putative target of Rho, on the Triton X-100-permeabilized smooth muscle of rabbit portal vein, Introduction of the constitutively active form of Rho-kinase into the cytosol of Triton X-100-permeabilized smooth muscle provoked a contraction and a proportional increase in levels of monophosphorylation of myosin light chain in both the presence and the absence of cytosolic Ca2+. These effects of constitutively active Rho-kinase were wortmannin (a potent myosin light chain kinase inhibitor)-insensitive. Immunoblot analysis revealed that the amount of native Rho-kinase was markedly lower in Triton X-100-permeabilized tissue than in intact tissue. Our results demonstrate that Rho-kinase directly modulates smooth muscle contraction through myosin light chain phosphorylation, independently of the Ca2+-calmodulin-dependent myosin light chain kinase pathway.