Analyses of activation mechanisms of cell mechanosensor at nano- and microlevels.

纳米和微米水平上细胞机械传感器的激活机制分析。

• 批准号: 15086207
• 负责人: SOKABE Masahiro
• 金额: $ 20.48万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15086207/
• 关键词: mechanosensor; mechanosensitive channel; MscL; ccytoskeleton; stress fiber; actin fiber; focal adhesion; zyxin; cofilin; セミインタクト細胞; アルファーアクチニン; 内皮細胞; メカノシグナリング; SAチャネル; インテグリン; メカノトランスダクション; 機械センサー; アクチン; 細胞膜

Virtually every cell can respond to mechanical stimuli, which plays a critical role in a variety of biofunctions including the regulations of cell volume, cell migration and cardiovascular system, and gravisensing. The molecular mechanisms underlying this function termed cell mechanosensing, however, had been unknown for a long time due to the ambiguity of the molecular entity of cell mechanosensors. Such situation was largely improved by the discovery of mechanosensitive (MS) channels, by which great progresses have been made in this field.Based on this background, we set the aim of the present study to resolve, 1) the mechanisms of MS channel activation, and the role of 2) cytoskeleton and 3) focal adhesion in cell mechanosensing. The obtained major results are as follows.1. Activation mechanism of MS channels: Using the best studied MS channel with known 3D structure, bacterial MscL, we tried to resolve its activation mechanism at the nanoscale level. We succeeded in identifying its mechanosensing site that resides near the surface of the outer leaflet of the membrane, by the combination of molecular biology, patch clamping, and molecular dynamics simulation. We also clarified that the channel opens its pore thorough the tilting and sliding of the transmemebrane helices upon sensing of membrane tension at the mechanosensing site.2. Role of cytoskeleton in mechanosensing: Using a semi-intact model of cultured endothelial cells, we found that the major structural component of stress fiber, actin fiber, can work as a new type of mechanosensor through its depolymelization in response to the tension decrease in the actin fiber.3. Role of focal adhesion in mechanosensing: Using a semi-intact model of cultured epithelial cell line, we found that the focal protein zyxin plays a critical role in the development of actin fibers and focal adhesions by mechanical stimuli.

几乎每个细胞都能对机械刺激产生反应，机械刺激在细胞体积调节、细胞迁移和心血管系统调节、重力感知等多种生物功能中起着至关重要的作用。然而，由于细胞机械传感器的分子实体不明确，长期以来，这种被称为细胞机械传感的功能的分子机制一直不为人所知。机械敏感（MS）通道的发现极大地改善了这一状况，使这一领域取得了重大进展。在此背景下，我们确定了本研究的目的，1)MS通道激活的机制，2)细胞骨架和3)局灶黏附在细胞机械传感中的作用。得到的主要结果如下：1。质谱通道的激活机制：利用已知三维结构的质谱通道细菌MscL，我们试图在纳米水平上解决其激活机制。通过分子生物学、贴片夹紧和分子动力学模拟的结合，我们成功地确定了其位于膜外小叶表面附近的机械传感位点。我们还澄清了在机械感应位点感知膜张力时，通道通过跨膜螺旋的倾斜和滑动打开其孔。细胞骨架在机械传感中的作用：通过半完整的内皮细胞培养模型，我们发现应力纤维的主要结构成分肌动蛋白纤维可以通过解聚来响应肌动蛋白纤维的张力降低，从而作为一种新型的机械传感器。局灶黏附在机械传感中的作用：利用培养上皮细胞系的半完整模型，我们发现局灶蛋白zyxin在肌动蛋白纤维的发育和机械刺激下的局灶黏附中起关键作用。

项目成果

Yoshimura K, Nomura T, Sokabe M: "Loss-of-function mutations at the rim of the funnel of mechanosensitive channel MscL"Biophys J. (印刷中). (2004)

Yoshimura K、Nomura T、Sokabe M：“机械敏感通道 MscL 漏斗边缘的功能丧失突变”Biophys J.（出版中）。

Tension-Dependent Formation of Stress Fibers in Fibroblasts : a Study Using Semi-Intact Cells.

成纤维细胞中应力纤维的张力依赖性形成：使用半完整细胞的研究。

• 发表时间: 2004
• 期刊: JSME Int J. 47(4)
• 作者: Hirata H;Tatsumi H;Sokabe M.
• 通讯作者: Sokabe M.

曽我部正博, 河上敬介, 早川公英, 成瀬恵治, 辰巳仁史: "内皮細胞の伸展依存性リモデリング -分子から形へのインターフェースを見る-"血管医学. 4. 237-244 (2003)

Masahiro Sogabe、Keisuke Kawakami、Kimihide Hayakawa、Keiji Naruse、Hitoshi Tatsumi：“内皮细胞的拉伸依赖性重塑 - 从分子到形状的界面 -”血管医学。

機械受容(Stretch Activated)チャネルの活性化抑制剤

机械敏感（拉伸激活）通道激活抑制剂

• 发表时间: 2004

Mechanosensitive BK Channel Activated by Membrane Stress Created by Amphipaths

由两栖动物产生的膜应力激活的机械敏感 BK 通道

• 发表时间: 2005
• 期刊: Mol Membr Biol. 22(6)
• 作者: Qu Z;Chi S;Su X;Naruse K;Sokabe M
• 通讯作者: Sokabe M