Homologs of the yeast Sec complex subunits Sec62p and Sec63p are abundant proteins in dog pancreas microsomes
Homologs of the yeast Sec complex subunits Sec62p and Sec63p are abundant proteins in dog pancreas microsomes
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DOI：
10.1073/pnas.97.13.7214
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发表时间：
2000-06-20
影响因子：
11.1
通讯作者：
Zimmermann, R
中科院分区：
文献类型：
--
作者：
Tyedmers, J;Lerner, M;Zimmermann, R
翻译后蛋白质转运到酵母内质网（ER）中涉及膜中所谓的Sec复合物，其包含类似的Sec 61 p亚复合物、推定的信号肽受体亚复合物和热休克蛋白40型亚基，Sec 63 p，最近，发现了酵母蛋白Sec62p和Sec63p的人类同源物。在这里，我们确定了这两种膜蛋白在狗胰腺微粒体中的浓度，并观察到酵母蛋白Sec62 p和Sec63 p的犬同源物是丰富的蛋白质，与Sec61 α p单体相比，以几乎等摩尔浓度存在。此外，我们检测到这两种蛋白质彼此结合以及与Sec61 p复合物结合的部分，人Sec63 p的J结构域显示与免疫球蛋白重链结合蛋白相互作用。因此，哺乳动物内质网的膜含有从酵母中的蛋白质易位酶中已知的组分。我们认为，这些组件所需的有效的共翻译蛋白运输到哺乳动物ER以及其他运输过程。
Cotranslational protein transport into dog pancreas microsomes involves the Sec61p complex plus a luminal heat shock protein 70, Posttranslational protein transport into the yeast endoplasmic reticulum (ER) involves the so-called Sec complex in the membrane, comprising a similar Sec61p subcomplex, the putative signal peptide receptor subcomplex, and the heat shock protein 40-type subunit, Sec63p, plus a luminal heat shock protein 70, Recently, human homologs of yeast proteins Sec62p and Sec63p were discovered. Here we determined the concentrations of these two membrane proteins in dog pancreas microsomes and observed that the canine homologs of yeast proteins Sec62p and Sec63p are abundant proteins, present in almost equimolar concentrations as compared with Sec61 alpha p monomers, Furthermore, we detected fractions of these two proteins in association with each other as well as with the Sec61p complex, The J domain of the human Sec63p was shown to interact with immunoglobulin heavy chain binding protein. Thus, the membrane of the mammalian ER contains components, known from the posttranslationally operating protein translocase in yeast. We suggest that these components are required for efficient cotranslational protein transport into the mammalian ER as well as for other transport processes.