<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.

钙调蛋白依赖性激酶对肌球蛋白轻链的磷酸化是钙调节平滑肌收缩的分子机制。然而，我们已经提出，肌动蛋白结合蛋白，命名为'leiotonin'，是真实的激活剂。在本研究中，获得了以下结果，所有这些都表明了“激酶活性”和收缩之间的差异。刺激活性：1）蛋白酶、CANP或胰蛋白酶消化“激活剂级分”<V_8>几乎不影响其激酶活性，但几乎完全破坏其收缩刺激活性; 2）化学修饰“激活剂级分”的Lys、Tyr或Cys残基导致其收缩刺激活性丧失，而保留其激酶活性; 3）激酶活性随pH从6.8升高至8.0而降低，而收缩刺激活性在该pH范围内几乎相同。

项目成果

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

Biochem.Biophys.Res.Commun.130。

Experimentia. 41. (1985)

实验。

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

生物化学。