Funcioal analysis of mouse EDEM, which eaocelerales gyocprotein ERAD

小鼠 EDEM 的功能分析，其中 eaocelerales 球蛋白 ERAD

基本信息

批准号：
13680780
负责人：
HOSOKAWA Nobuko
金额：
$ 1.66万
依托单位：
KYOTO 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

Newly synthesized proteins in the ER(endoplasmic reticulum) are sorted out to the secretory pathway after they fold or assemble correctly, while misfoled or misassembled proteins are retained in the ER. This mechanism is known as ER quality control. Misfolded proteins in the ER are retrotranslocated out of the ER,followed by degradation by cytosolic proteasome, which is called as ERAD(ER associated degradation). We have cloned a mouse gene, and named it as EDEM(ER degradation enhancing α-mannosidase like-protein), which accelerated the ERAD of misfolded glycoproteins.In the present study, we have clarified the followings:1. We are usingα1-antitrypsin variant null (Hong Kong) (NHK)as a model substrate for ERAD. It is known that the mannose trimming by the ER Mannosidase I(ER Man I) become the signal for glycoprotein ERAD. We have clarified that overexpression of ER Man I into human embryonic kidney 293 cells enhanced the degration of NHK. We also found that the effect of ER Man I and EDEM are additive. We conclude that the misfolded glycoproteins are recognized both by ER Man I and by EDEM before they are degraded2. NHK has one cysteine residue near its Cterminus, thus it is possible that they make disulfide-bonded dimer. We have clarified that NHK make homodimer within the cells, and that coexpression of EDEM inhibited the dimer formation. Disulfide-bonded dimer is expectedly retrotraslocated out of the ER less effciently. On the contrary, EDEM did not affect the secretion or degradation of wild type α1-antitrypsin, which folds correctly in the ER. Taken together, we expect that EDEM keep the misfolded glycoprotein degradation competent

ER中新合成的蛋白质（内质网）在折叠折叠或正确组装后将其分类到秘密途径中，同时将错误折叠或错误填充的蛋白保留在ER中。该机制称为ER质量控制。 ER中错误折叠的蛋白质被转移到ER中，然后通过胞质蛋白酶体降解，称为Erad（ER相关的降解）。我们已经克隆了一个小鼠基因，并命名为ER甘露糖苷酶I（ER甘露糖苷酶I）的甘露糖修剪成为糖蛋白ERAD的信号。我们已经澄清了将Er Man I的过表达在人类胚胎肾脏293个细胞中增强了NHK的程度。我们还发现添加了Er Man I和Edem的效果。我们包括，在脱脂之前，err e i coption蛋白均被Er Man I和Edem认识到2。 NHK在其CTERMINUS附近具有一个半胱氨酸的保留率，因此它们可能使二硫键二聚体。我们已经阐明了NHK在细胞内产生同型二聚体，而EDEM的共表达抑制了二聚体的形成。预计将二硫键二聚体被转移到ER中的偏移率较低。相反，EDEM不影响野生型α1-抗胰蛋白酶的分泌或降解，后者在ER中正确折叠。综上所述，我们希望Edem保持错误折叠的糖蛋白降解能力