Sec61p is the main ribosome receptor in the endoplasmic reticulum of Saccharomyces cerevisiae
Sec61p is the main ribosome receptor in the endoplasmic reticulum of Saccharomyces cerevisiae
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DOI：
10.1515/bc.2000.126
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发表时间：
2000-09-01
影响因子：
3.7
通讯作者：
Kalies, KU
中科院分区：
文献类型：
--
作者：
Prinz, A;Hartmann, E;Kalies, KU
共转位蛋白转位到内质网(ER)的一个特征是翻译的核糖体与膜上的转位部位紧密联系。生化分析表明，Sec61复合体是哺乳动物细胞内质网中的主要核糖体受体。用分别来自酿酒酵母、Sec61p复合体和Ssh1p复合体的纯化同源物进行的类似实验表明，它们以与哺乳动物Sec61复合体相似的亲和力结合核糖体。然而，这些研究并不排除酵母ER中可能形成丰富的核糖体结合位点的其他蛋白质的存在。我们现在在这里表明，与在哺乳动物中发现的情况类似，在酿酒酵母中，两个Sec61-同系物Sec61p和Ssh1p对于在ER膜上形成高亲和力的核糖体结合位点是必不可少的。在标准生长条件下，Ssh1p形成的结合位点数至少比Sec61p少4倍。
A characteristic feature of the co-transtational protein translocation into the endoplasmic reticulum (ER) is the tight association of the translating ribosomes with the translocation sites in the membrane. Biochemical analyses identified the Sec61 complex as the main ribosome receptor in the ER of mammalian cells. Similar experiments using purified homologues from the yeast Saccharomyces cerevisiae, the Sec61p complex and the Ssh1p complex, respectively, demonstrated that they bind ribosomes with an affinity similar to that of the mammalian Sec61 complex. However, these studies did not exclude the presence of other proteins that may form abundant ribosome binding sites in the yeast ER. We now show here that similar to the situation found in mammals in the yeast Saccharomyces cerevisiae the two Sec61-homologues Sec61p and Ssh1p are essential for the formation of high-affinity ribosome binding sites in the ER membrane. The number of binding sites formed by Ssh1p under standard growth conditions is at least 4 times less than those formed by Sec61p.