A novel quality control compartment derived from the endoplasmic reticulum
| Autor: | Gerardo Z. Lederkremer, Sharon Vigodman Fromm, Shiri Kamhi-Nesher, Marina Shenkman, Rachel Ehrlich, Sandra Tolchinsky |
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| Rok vydání: | 2001 |
| Předmět: |
Time Factors
Calnexin Vesicular Transport Proteins Genes MHC Class I Golgi Apparatus Endoplasmic Reticulum Histones chemistry.chemical_compound Mice Cytosol Cricetinae Trypsin biology 3T3 Cells Brefeldin A Translocon Cell biology Cysteine Endopeptidases Protein Transport Ribonucleoproteins symbols Electrophoresis Polyacrylamide Gel Subcellular Fractions Sec61 Proteasome Endopeptidase Complex Octoxynol Detergents Immunoblotting Nerve Tissue Proteins CHO Cells Article symbols.namesake Munc18 Proteins Multienzyme Complexes Animals Molecular Biology Ubiquitins Secretory pathway Glycoproteins Dose-Response Relationship Drug Endoplasmic reticulum Calcium-Binding Proteins Cell Membrane Cell Biology Golgi apparatus Precipitin Tests Protein Structure Tertiary chemistry Microscopy Fluorescence biology.protein Calreticulin |
| Zdroj: | Molecular biology of the cell. 12(6) |
| ISSN: | 1059-1524 |
| Popis: | Degradation of proteins that, because of improper or suboptimal processing, are retained in the endoplasmic reticulum (ER) involves retrotranslocation to reach the cytosolic ubiquitin-proteasome machinery. We found that substrates of this pathway, the precursor of human asialoglycoprotein receptor H2a and free heavy chains of murine class I major histocompatibility complex (MHC), accumulate in a novel preGolgi compartment that is adjacent to but not overlapping with the centrosome, the Golgi complex, and the ER-to-Golgi intermediate compartment (ERGIC). On its way to degradation, H2a associated increasingly after synthesis with the ER translocon Sec61. Nevertheless, it remained in the secretory pathway upon proteasomal inhibition, suggesting that its retrotranslocation must be tightly coupled to the degradation process. In the presence of proteasomal inhibitors, the ER chaperones calreticulin and calnexin, but not BiP, PDI, or glycoprotein glucosyltransferase, concentrate in the subcellular region of the novel compartment. The “quality control” compartment is possibly a subcompartment of the ER. It depends on microtubules but is insensitive to brefeldin A. We discuss the possibility that it is also the site for concentration and retrotranslocation of proteins that, like the mutant cystic fibrosis transmembrane conductance regulator, are transported to the cytosol, where they form large aggregates, the “aggresomes.” |
| Databáze: | OpenAIRE |
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