A second trimeric complex containing homologs of the Sec61p complex functions in protein transport across the ER membrane of S. cerevisiae.
A second trimeric complex containing homologs of the Sec61p complex functions in protein transport across the ER membrane of S. cerevisiae.
复制标题
含有 Sec61p 复合物同源物的第二个三聚复合物在跨酿酒酵母 ER 膜的蛋白质转运中发挥作用。
作者：
K. Finke;K. Plath;S. Panzner;S. Prehn;T. Rapoport;E. Hartmann;T. Sommer
酵母微粒体含有参与翻译后蛋白转运的七聚体Sec复合物，其由异源三聚体Sec 61 p复合物和四聚体Sec 62-Sec 63复合物组成。三聚体Sec 61 p复合物也作为一个单独的实体存在，可能在共翻译蛋白质转运中发挥作用，就像哺乳动物中的同系物一样。我们现在已经在酵母内质网膜中发现了第二个结构相关的三聚体复合物，命名为Ssh 1 p复合物。它由Ssh 1 p1（Sec 61 homolog 1），一个相当遥远的亲戚Sec 61 p，Sbh 2 p，一个同系物的Sbh 1 p亚基的Sec 61 p复合物，和Sss 1 p，一个共同的组成部分，两个三聚体复合物。与Sec 61 p相反，Ssh 1 p对细胞活力不是必需的，但它是正常生长速率所必需的。Sbh 1 p和Sbh 2 p单独也不是必需的，但缺乏这两种蛋白质的细胞在高温下生长受损，并积累分泌蛋白的前体;从这些细胞中分离的微粒体也表现出翻译后蛋白质转运速率降低。与Sec 61 p复合物一样，Ssh 1 p复合物与膜结合核糖体相互作用，但它不与Sec 62-Sec 63 p复合物结合形成七聚体Sec复合物。因此，我们认为它只在蛋白质转运的共翻译途径中发挥作用。
Yeast microsomes contain a heptameric Sec complex involved in post‐translational protein transport that is composed of a heterotrimeric Sec61p complex and a tetrameric Sec62‐Sec63 complex. The trimeric Sec61p complex also exists as a separate entity that probably functions in co‐translational protein transport, like its homolog in mammals. We have now discovered in the yeast endoplasmic reticulum membrane a second, structurally related trimeric complex, named Ssh1p complex. It consists of Ssh1p1 (Sec sixty‐one homolog 1), a rather distant relative of Sec61p, of Sbh2p, a homolog of the Sbh1p subunit of the Sec61p complex, and of Sss1p, a component common to both trimeric complexes. In contrast to Sec61p, Ssh1p is not essential for cell viability but it is required for normal growth rates. Sbh1p and Sbh2p individually are also not essential, but cells lacking both proteins are impaired in their growth at elevated temperatures and accumulate precursors of secretory proteins; microsomes isolated from these cells also exhibit a reduced rate of post‐translational protein transport. Like the Sec61p complex, the Ssh1p complex interacts with membrane‐bound ribosomes, but it does not associate with the Sec62‐Sec63p complex to form a heptameric Sec complex. We therefore propose that it functions exclusively in the co‐translational pathway of protein transport.
影响因子：
3.3
作者：
M. Scidmore;Heid H. Okamura;M. Rose
通讯作者：
M. Scidmore;Heid H. Okamura;M. Rose
影响因子：
3.3
作者：
KURIHARA, T;SILVER, P
通讯作者：
SILVER, P