Hartmann E, Sommer T, Prehn S, Görlich D, Jentsch S, Rapoport T A
Max-Delbrück Centre for Molecular Medicine, Berlin-Buch, Germany.
Nature. 1994 Feb 17;367(6464):654-7. doi: 10.1038/367654a0.
Protein translocation into the mammalian endoplasmic reticulum requires the Sec61p complex, which consists of three membrane proteins. The alpha-subunit, the homologue of Sec61p of yeast, shows some similarity to SecYp, a key component of the protein export apparatus of bacteria. In Escherichia coli, SecYp is also associated with two other proteins (SecEp and band-1 protein). We have now determined the sequences of the beta- and gamma-subunits of the mammalian Sec61p complex. Sec61-gamma is homologous to SSS1p, a suppressor of sec61 mutants in Saccharomyces cerevisiae, and can functionally replace it in yeast cells. Moreover, Sec61-gamma and SSS1p are structurally related to SecEp of E. coli and to putative homologues in various other bacteria. At least two subunits of the Sec61/SecYp complex therefore seem to be key components of the protein translocation apparatus in all classes of organisms.
蛋白质转运到哺乳动物内质网需要Sec61p复合体，该复合体由三种膜蛋白组成。α亚基是酵母Sec61p的同源物，与细菌蛋白质输出装置的关键成分SecYp有一些相似之处。在大肠杆菌中，SecYp还与另外两种蛋白质（SecEp和带1蛋白）相关联。我们现已确定了哺乳动物Sec61p复合体的β和γ亚基的序列。Sec61-γ与酿酒酵母sec61突变体的抑制因子SSS1p同源，并且可以在酵母细胞中发挥其功能。此外，Sec61-γ和SSS1p在结构上与大肠杆菌的SecEp以及其他各种细菌中的假定同源物相关。因此，Sec61/SecYp复合体的至少两个亚基似乎是所有生物类群中蛋白质转运装置的关键成分。
