RRC ID 29205
Author Nishikawa S, Hirata A, Nakano A.
Title Inhibition of endoplasmic reticulum (ER)-to-Golgi transport induces relocalization of binding protein (BiP) within the ER to form the BiP bodies.
Journal Mol. Biol. Cell
Abstract Immunofluorescence staining of yeast cells with anti-binding protein (BiP) antibodies shows uniform staining of the endoplasmic reticulum (ER). We have found that overproduction of Sec12p, an ER membrane protein, causes a change of BiP distribution within the cell. Upon induction of Sec12p by the GAL1 promoter, the staining pattern of BiP turns into bright dots scattering in the cell, whereas the staining of Sec12p remains to be the typical ER figure. Overproduction of other ER membrane proteins, HMG-CoA reductase or Sed4 protein, does not induce such relocalization of BiP. Pulse-chase experiments and electron microscopy have revealed that the overproduction of Sec12p inhibits protein transport from the ER to the Golgi apparatus. When the transport is arrested by one of the sec mutations that block the ER-to-Golgi step at the restrictive temperature, the BiP staining also changes into the punctate pattern. In contrast, the sec mutants that block later or earlier steps of the secretory pathway do not induce such change of BiP localization. These observations indicate that relocalization of BiP is caused by the inhibition of ER-to-Golgi transport. Using immunoelectron microscopy, we have found that the punctate staining is because of the accumulation of BiP in the restricted region of the ER, which we propose to call the "BiP body." This implicates existence of ER subdomains in yeast. A vacuolar protein, proteinase A, appears to colocalize in the BiP body when the ER-to-Golgi transport is blocked, suggesting that the BiP body may have a role as the site of accumulation of cargo molecules before exit from the ER.
Volume 5(10)
Pages 1129-43
Published 1994-10
PMID 7865879
PMC PMC301136
MeSH Base Sequence Biological Transport, Active DNA, Fungal / genetics Endoplasmic Reticulum / metabolism* Endoplasmic Reticulum / ultrastructure Fluorescent Antibody Technique Fungal Proteins / biosynthesis Fungal Proteins / genetics Fungal Proteins / metabolism* Genes, Fungal Glycoproteins / metabolism Golgi Apparatus / metabolism* Golgi Apparatus / ultrastructure Guanine Nucleotide Exchange Factors HSP70 Heat-Shock Proteins / genetics HSP70 Heat-Shock Proteins / metabolism* Inclusion Bodies / metabolism Inclusion Bodies / ultrastructure Membrane Glycoproteins / biosynthesis Membrane Glycoproteins / genetics Microscopy, Immunoelectron Models, Biological Molecular Sequence Data Saccharomyces cerevisiae / genetics Saccharomyces cerevisiae / metabolism Saccharomyces cerevisiae / ultrastructure Saccharomyces cerevisiae Proteins*
IF 3.905
Times Cited 69
DNA material pSHY13-2 (RDB08867) pSHY15-1 (RDB08869) pSHY14-5 (RDB08868)