STUDY ON THE STRUCTURE FUNCTION AND PHYSIOLOGICAL ROLES OF SA CHANNELS

SA通道的结构功能及生理作用研究

• 批准号: 13480216
• 负责人: SOKABE Masahiro
• 金额: $ 9.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13480216/
• 关键词: SA channel; Structure-Function; Kca chahnel; Bacterial SA channel; Cytoskeleton; Integrin; Mechanical Stress; Cell Signaling; 心筋; NF-KB; ストレス; リン酸化; 接着斑; Mid1; シロイヌナズナ

The aim of this study was three fold : 1) elucidation of structure function of SA channels with known structure, 2) molecular identification of SA channels from higher order organisms, and 3) elucidation of roles of SA channels and cytoskeletons in mechano-induced cell signaling. Major results are as follows. (1) Identification of mechano-sensitive domain of the bacterial SA channel MscL : We found that hydrophobic amino-residues located at the peri-plasmic boundary of the lipid bilayer act as a mechanosensor of MscL. This site corresponds to the lipid glycerol backbone that is the most suitable structure for sensing tension in the membrane. (2)Molecular identification of the heart SA channel SAKCA : We cloned a gene encoding a stretch activated big Kca channel from chick heart and identified the 59 amino acids sequence called STREX at C-terminus as a mechanosensitive domain of this channel. We also isolated a 50 KDa protein acting as an accessory device that conveys tension in the membrane to STREX. (3) Role of cytosekelton in SA channel activation : We found that the stress fiber acts as a force transmitter in SA channel activation. (4) Role of SA channel in cell signaling : We analyzed the intracellular signaling leading to NF-kB activation in response to mechanical stimuli. It is suggested that cells can chose different mechano-signaling cascade depending on the time structure of mechanical stmuli. Mechano-signaling to cyclic or transient mechanical stimuli is mainly mediated by SA channels, while those to constant mechanical stimuli by integrin

本研究的目的有三个方面：1）阐明已知结构的SA通道的结构功能，2）从更高级生物中鉴定SA通道的分子，3）阐明SA通道和细胞骨架在机械诱导的细胞信号传导中的作用。主要结果如下。(1)细菌SA通道MscL的机械敏感结构域的鉴定：我们发现位于脂双层周质边界的疏水氨基残基充当MscL的机械传感器。该位点对应于脂质甘油骨架，其是用于感测膜中张力的最合适的结构。（2）心脏SA通道SAKCA的分子鉴定：从鸡心脏中克隆了一个编码牵张激活的大KCA通道的基因，并鉴定了该通道C端59个氨基酸的序列STREX为机械敏感结构域。我们还分离出一种50 KDa的蛋白质，作为一种辅助装置，将膜中的张力传递给STREX。(3)细胞壁在SA通道激活中的作用：我们发现应力纤维在SA通道激活中起着力传递的作用。(4)SA通道在细胞信号传导中的作用：我们分析了机械刺激导致NF-κ B激活的细胞内信号传导。提示细胞可以根据力学刺激的时间结构选择不同的力学信号级联。对周期性或瞬时性机械刺激的机械信号主要由SA通道介导，而对恒定性机械刺激的机械信号主要由整合素介导

项目成果

Kobayashi S, Nagino M, Komatsu S, Naruse K, Nimura Y, Nakanishi M, Sokabe M.: "Stretch-induced IL-6 secretion from endothelial cells requires NF-KB activation."Biochem.Bhiophys.Res.Com.. 308. 306-312 (2003)

Kobayashi S、Nagino M、Komatsu S、Naruse K、Nimura Y、Nakanishi M、Sokabe M.：“拉伸诱导内皮细胞分泌 IL-6 需要 NF-KB 激活。”Biochem.Bhiophys.Res.Com.. 308

Kawakami K, Tatsumi H, Sokabe M.: "Dymanics of integrin at focal adhesion in endothelial cells detected by near field microscopy."J Cell Sci. 114・17. 3125-3135 (2001)

Kawakami K、Tatsumi H、Sokabe M.：“通过近场显微镜检测内皮细胞粘着斑处的整合素动力学。”J Cell Sci 114・17（2001）。

Hoshino T, Tatsumi H, Nakashima T, Sokabe M: "In vitro Reconstitution of Signal Transmission from a Hair Cell to the Growth Cone of a Chick Vestibular Ganglion Cell"Neurosci. 120. 993-1003 (2003)

Hoshino T、Tatsumi H、Nakashima T、Sokabe M：“体外重建从毛细胞到鸡前庭神经节细胞生长锥的信号传输”Neurosci。

曽我部正博, 郷信広(編): "生物物理学とはなにか"共立出版. 288 (2003)

Masahiro Sogabe、Nobuhiro Go（编辑）：“什么是生物物理学？” 288 (2003)

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

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