Cargando…

Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae

To clarify the roles of Kar2p (BiP) and Sec63p in translocation across the ER membrane in Saccharomyces cerevisiae, we have utilized mutant alleles of the essential genes that encode these proteins: kar2-203 and sec63-1. Sanders et al. (Sanders, S. L., K. M. Whitfield, J. P. Vogel, M. D. Rose, and R...

Descripción completa

Detalles Bibliográficos
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1995
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120636/
https://www.ncbi.nlm.nih.gov/pubmed/8522580
_version_ 1782141541602557952
collection PubMed
description To clarify the roles of Kar2p (BiP) and Sec63p in translocation across the ER membrane in Saccharomyces cerevisiae, we have utilized mutant alleles of the essential genes that encode these proteins: kar2-203 and sec63-1. Sanders et al. (Sanders, S. L., K. M. Whitfield, J. P. Vogel, M. D. Rose, and R. W. Schekman. 1992. Cell. 69:353-365) showed that the translocation defect of the kar2-203 mutant lies in the inability of the precursor protein to complete its transit across the membrane, suggesting that the lumenal hsp70 homologue Kar2p (BiP) binds the transiting polypeptide in order to facilitate its passage through the pore. We now show that mutation of a conserved residue (A181-->T) (Nelson, M. K., T. Kurihara, and P. Silver. 1993. Genetics. 134:159- 173) in the lumenal DnaJ box of Sec63p (sec63-1) results in an in vitro phenotype that mimics the precursor stalling defect of kar2-203. We demonstrate by several criteria that this phenotype results specifically from a defect in the lumenal interaction between Sec63p and BiP: Neither a sec62-1 mutant nor a mutation in the cytosolically exposed domain of Sec63p causes precursor stalling, and interaction of the sec63-1 mutant with the membranebound components of the translocation apparatus is unimpaired. Additionally, dominant KAR2 suppressors of sec63-1 partially relieve the stalling defect. Thus, proper interaction between BiP and Sec63p is necessary to allow the precursor polypeptide to complete its transit across the membrane.
format Text
id pubmed-2120636
institution National Center for Biotechnology Information
language English
publishDate 1995
publisher The Rockefeller University Press
record_format MEDLINE/PubMed
spelling pubmed-21206362008-05-01 Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae J Cell Biol Articles To clarify the roles of Kar2p (BiP) and Sec63p in translocation across the ER membrane in Saccharomyces cerevisiae, we have utilized mutant alleles of the essential genes that encode these proteins: kar2-203 and sec63-1. Sanders et al. (Sanders, S. L., K. M. Whitfield, J. P. Vogel, M. D. Rose, and R. W. Schekman. 1992. Cell. 69:353-365) showed that the translocation defect of the kar2-203 mutant lies in the inability of the precursor protein to complete its transit across the membrane, suggesting that the lumenal hsp70 homologue Kar2p (BiP) binds the transiting polypeptide in order to facilitate its passage through the pore. We now show that mutation of a conserved residue (A181-->T) (Nelson, M. K., T. Kurihara, and P. Silver. 1993. Genetics. 134:159- 173) in the lumenal DnaJ box of Sec63p (sec63-1) results in an in vitro phenotype that mimics the precursor stalling defect of kar2-203. We demonstrate by several criteria that this phenotype results specifically from a defect in the lumenal interaction between Sec63p and BiP: Neither a sec62-1 mutant nor a mutation in the cytosolically exposed domain of Sec63p causes precursor stalling, and interaction of the sec63-1 mutant with the membranebound components of the translocation apparatus is unimpaired. Additionally, dominant KAR2 suppressors of sec63-1 partially relieve the stalling defect. Thus, proper interaction between BiP and Sec63p is necessary to allow the precursor polypeptide to complete its transit across the membrane. The Rockefeller University Press 1995-12-01 /pmc/articles/PMC2120636/ /pubmed/8522580 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae
title Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae
title_full Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae
title_fullStr Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae
title_full_unstemmed Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae
title_short Interaction between BiP and Sec63p is required for the completion of protein translocation into the ER of Saccharomyces cerevisiae
title_sort interaction between bip and sec63p is required for the completion of protein translocation into the er of saccharomyces cerevisiae
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2120636/
https://www.ncbi.nlm.nih.gov/pubmed/8522580