Glycopeptide export from the endoplasmic reticulum into cytosol is mediated by a mechanism distinct from that for export of misfolded glycoprotein.
Glycopeptide export from the endoplasmic reticulum into cytosol is mediated by a mechanism distinct from that for export of misfolded glycoprotein.
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糖肽从内质网输出到细胞质中是通过与错误折叠糖蛋白输出不同的机制介导的。
作者：
Tadashi Suzuki;W. Lennarz
当在内质网（ER）中形成的糖蛋白被错误折叠时，它们通常被转位到胞质溶胶中进行泛素化，随后被蛋白酶体降解。这个系统，即所谓的ER相关糖蛋白降解，对于真核生物维持ER中产生的糖蛋白的质量是重要的。在酵母中已经确定，几种不同的蛋白质参与这种移位和降解过程。ER中形成的小糖肽以类似的方式输出到胞质溶胶。这种糖肽输出系统从酵母到哺乳动物细胞都是保守的，这表明它对真核细胞具有基本的生物学意义。这两个输出系统（错误折叠的糖蛋白和糖肽）共享一些特性，如需要ATP和Sec 61 p的参与，Sec 61 p是一种中央膜蛋白，可能形成蛋白质输出的错位通道。然而，糖肽输出的机制知之甚少。在这项研究中，各种突变体已知有出口/降解错误折叠的糖蛋白的影响，检查糖肽出口活性与新建立的测定方法。令人惊讶的是，发现大多数突变体在糖肽输出方面没有表现出缺陷。唯一的基因，被认为是所需的有效输出的两种类型的基板是PMR 1，基因编码的中间高尔基体Ca（2+）/Mn（2+）-离子泵。这些结果提供的证据表明，虽然参与输出错误折叠的糖蛋白和糖肽的系统共享一些特性，但它们表现出明显的差异。
When glycoproteins formed in the endoplasmic reticulum (ER) are misfolded, they are generally translocated into the cytosol for ubiquitination and are subsequently degraded by the proteasome. This system, the so-called ER-associated glycoprotein degradation, is important for eukaryotes to maintain the quality of glycoproteins generated in the ER. It has been established in yeast that several distinct proteins are involved in this translocation and degradation processes. Small glycopeptides formed in the ER are exported to the cytosol in a similar manner. This glycopeptide export system is conserved from yeast to mammalian cells, suggesting its basic biological significance for eukaryotic cells. These two export systems (for misfolded glycoproteins and glycopeptides) share some properties, such as a requirement for ATP and involvement of Sec61p, a central membrane protein presumably forming a dislocon channel for export of proteins. However, the machinery of glycopeptide export is poorly understood. In this study, various mutants known to have an effect on export/degradation of misfolded glycoproteins were examined for glycopeptide export activity with a newly established assay method. Surprisingly, most of the mutants were found not to exhibit a defect in glycopeptide export. The only gene that was found to be required on efficient export of both types of substrates was PMR1, the gene encoding the medial-Golgi Ca(2+)/Mn(2+)-ion pump. These results provide evidence that although the systems involved in export of misfolded glycoproteins and glycopeptides share some properties, they have exhibited distinct differences.
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内质网相关降解的 HRD 基因依赖性。
影响因子：
3.3
作者：
Wilhovsky,S;Gardner,R;Hampton,R
通讯作者：
Hampton,R
影响因子：
2.7
作者：
R. Elble
通讯作者：
R. Elble
影响因子：
4
作者：
F. Urano;A. Bertolotti;D. Ron
通讯作者：
F. Urano;A. Bertolotti;D. Ron
影响因子：
16
作者：
Casagrande, R;Stern, P;Ploegh, H
通讯作者：
Ploegh, H
在酵母中，小糖肽从内质网输出到细胞质中不受其寡糖链结构的影响。
影响因子：
4.3
作者：
Suzuki,T;Lennarz,WJ
通讯作者：
Lennarz,WJ