权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Mechanism of organelle targeting and topogenesis of membrane proteins

膜蛋白的细胞器靶向和拓扑发生机制

基本信息

批准号：
15013244
负责人：
SAKAGUCHI Masao
金额：
$ 10.24万
依托单位：
University of Hyogo (2004)Kyushu University (2003)
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 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15013244/
关键词：
Biomembrane Organelle Signal sequence Topology Membrane protein Biosynthesis

项目摘要

The primary objective of this study is to establish a reliable system for prediction of membrane topology, intracellular localization, and function of all membrane proteins encoded in the genome through elucidation of principal mechanisms for the topogenic process and the localization. On the basis of topogenic mechanisms on the endoplasmic reticulum, we have extensively examined the membrane integration of all the transmembrane segment of typical multispanning membrane proteins. We demonstrated that the type I signal anchor sequence can translocate N-terminal domain which is longer than we have expected. For the long N-domain translocation, no nucleotide triphosphates, no lumenal hsp70-homologue (BiP) are required. Ribosome plays an essential role for the translocation even after membrane targeting. The driving force for the N-domain translocation at the initial step is larger than that for the following continuous translocation. Furthermore, we systematically examined the signal sequences for targeting of membrane proteins to mitochondria and peroxisome. The long mitochondrial targeting presequence suppresses the co-translational targeting of hydrophobic membrane proteins to the endoplasmic reticulum mediated by signal recognition particle and translocon, and mediates the post-translational targeting to mitochondria. We elucidated targeting signals of mitochondrial outer membrane proteins, TOM22 and TOM20. To address the molecular mechanism of recognition of mitochondrial signal sequence, we established the system for expression, purification, and refolding of mitochondrial outer membrane protein translocation channel, TOM40.

本研究的主要目的是建立一个可靠的系统预测膜拓扑结构，细胞内定位，和功能的基因组中编码的所有膜蛋白，通过阐明的主要机制的拓扑过程和本地化。在内质网拓扑发生机制的基础上，我们广泛地研究了典型多跨膜蛋白的所有跨膜片段的膜整合。我们证明了I型信号锚序列可以转位的N-末端结构域比我们预期的要长。对于长的N-结构域易位，不需要核苷酸三磷酸，不需要内腔hsp 70同源物（BiP）。即使在膜靶向后，核糖体也对易位起着至关重要的作用。N结构域在起始阶段移位的驱动力大于后续连续移位的驱动力。此外，我们系统地研究了膜蛋白靶向线粒体和过氧化物酶体的信号序列。长线粒体靶向前序列抑制了疏水膜蛋白通过信号识别颗粒和易位子介导的共翻译靶向内质网，并介导了翻译后靶向线粒体。我们阐明了线粒体外膜蛋白TOM 22和TOM 20的靶向信号。为了研究线粒体信号序列识别的分子机制，我们建立了线粒体外膜蛋白转运通道TOM 40的表达、纯化和复性系统。