<Ca^(2+)> regulatory mechanism of smooth muscle contraction

<Ca^(2)>平滑肌收缩的调节机制

• 批准号: 59440025
• 负责人: EBASHI Setsuro
• 金额: $ 12.48万
• 依托单位: Okazaki National Research Institutes
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1984
• 资助国家: 日本
• 起止时间: 1984 至 1985
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-59440025/
• 关键词: 平滑筋収縮の【Ca^(2+)】調節; ライオトニン; ミオシン軽鎖リン酸化

Phosphorylation of myosin light chains by Ca-calmodulin dependent kinase is now widely believed to be the molecular mechanism of Ca-regulated activation of smooth muscle contraction. We have, however, proposed that the actin-binding protein, named 'leiotonin', is the real activator. In the present study, following results have been obtained, all of which demonstrate the discrepancy between 'kinase activity' and contraction-. stimulating activity.1) Digestion of 'activator fraction' by <V_8> protease, CANP or trypsin scarcely affected its kinase activity, but almost completely destroyed its contraction-stimulating activity.2) Chemical modification of Lys, Tyr or Cys residues of 'activator fraction' resulted in the loss of its contraction-stimulating activity, while sparing its kinase activity.3) Kinase activity was decreased with increase in pH from 6.8 to 8.0, while contraction-stimulating activity was almost the same in that range of pH.

现在，人们普遍认为，通过Ca-钙调蛋白依赖性激酶对肌球蛋白光链的磷酸化是平滑肌收缩激活的分子机制。但是，我们提出的是肌动蛋白结合蛋白，称为“ Leiotonin”，是真正的激活剂。在本研究中，已经获得了以下结果，所有这些都证明了“激酶活性”与收缩 - - 。 1）通过<V_8>蛋白酶，CANP或胰蛋白酶几乎不会影响其激酶活性，但几乎完全破坏其在质量的活动中，“激活剂的化学修饰”的化学修饰是“激活剂”的化学变化，而在其构成的活性中会导致KIN逐渐增加，但几乎完全破坏了其在KIN的活动中，从而使lys或Cys的残留物的化学变化在KIN中丧失，从而，刺激活性。 6.8至8.0，而在该pH的范围内，刺激性刺激活性几乎相同。

项目成果

Biochem.Biophys.Res.Commun.130. (1985)

Biochem.Biophys.Res.Commun.130。

Biochem. Biophys. Res. Commun.130. (1985)

生物化学。

Experimentia. 41. (1985)

实验。