Structure, function and regulation of Na^+/H^+ antiporters and intracellular localization mechanism.

Na^/H^反向转运蛋白的结构、功能和调控以及细胞内定位机制。

基本信息

批准号：
13680689
负责人：
KANAZAWA Hiroshi
金额：
$ 2.24万
依托单位：
Department of Biological Sciences, Graduate School of Science, Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Maintaining homeostasis of intracellular ion concentrations is the most basic requirement for every living cells. This mechanism is supported by various ion transpoting proteins located in cellular membranes. Na^+/H^+ antiporters among the ion-transporting proteins play a central role to maintain intracellular Na^+ and H^+ concentrations and named Nha or NHE, for bacteria or mammalian cells, respectively. In the present study, we set a final goal of this project to clarify the molecular basis of adaptation mechanism of living cells to various ion environments, especially Na^+ and H^+, by analyzing structure, function and regulation of Na^2/H^+ antiporters from bacteria, yeast and mammalian cells. During 2 years project term, we successfully obtained several new information of Na^+/H^2 antiporters as follows: (1) We clarified transmembrane domains essential for ion transport as well as domains required for pH sensing. We showed that H. pylori antiporter have a specific structure for pH … More sensing which is different from E. coli antiproter. We also successfully purified H. pylon antiporters and reconstituted the antiporter activity in vitro. (2) We showed that various different yeast species have similar Na^+/H^+ (Nhalp) by cloning the genes. We also found that Nhalp has a two-domain structure, comprised of hydrophobic membrane region, and hydrophilic cytoplasmic region which overall structure is close to mammalian NHE. Within this cytoplasmic region, we revealed that domains important for antiport and also intracellular localization exist. Further we identified that a novel membrane protein binds to the domain and enhance the antiporter activity. (3) We identified a novel Ca^<2+> protein (CHP) capable of binding to NHE previously. In this project we identified a new protein kinase and a new kinesin as the binding target of CHP. We studied functional significance of CHP in vitro and in vivo and discussed the multifunction of CHP. Further study is required for understanding intracellular regulatory function of CHP in the future study.The several different lines of result in terms of Na^+/H^+ antiporters in this project opened a new future study. The results were published as 6 independent full papers. Less

维持细胞内的体内稳态是每个活细胞的摩擦性需求。通过分析Na^2/H^+的结构，功能和调节，^+浓度nha或nhe nhe nha或nhe nhe nha或nhe nhe nha或nhe nhe nha或nhe nhe an来自2年的Bactteria lian细胞。对于pH，更多的传感与大肠杆菌的抗植物不同还发现，NHALP具有两域结构，疏水性膜区域，以及在toplasmic区域内的整体结构在这个项目中，我们能够与NHE结合的新型Ca^<2+。在未来的研究中了解CHP的细胞内调节功能。较少的。