Sec61p and BiP directly facilitate polypeptide translocation into the ER

摘要: Secretory proteins are segregated from cytosolic by their translocation into the endoplasmic reticulum (ER). A modified secretory protein trapped during across ER membrane can be crosslinked to two previously identified proteins, Sec61p and BiP (Kar2p). The dependence of this cross-linking upon small molecules was examined. Mutations in SEC62 SEC63 decrease ability cross-linked polypeptide translocation. ATP is also required for interaction with protein. Three kar2 alleles display defective vitro. Two these third allele, while exhibiting a severe defect, does not affect These results suggest that directly involved acts at stages cycle.