Cotranslocational Degradation Protects the Stressed Endoplasmic Reticulum from Protein Overload.
From: Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA.
Cell
- Publish Date: Aug 2006
- ISSN: 0092-8674
- Volume: 126
- Issue: 4
- Pages: 727-39
- Medium: Print
- Language: English
- Citation (JAMA): Oyadomari Seiichi, Yun Chi, Fisher Edward A, et al. Cotranslocational Degradation Protects the Stressed Endoplasmic Reticulum from Protein Overload.. Cell Aug 2006;126:727-39
Abstract
The ER’s capacity to process proteins is limited, and stress caused by accumulation of unfolded and misfolded proteins (ER stress) contributes to human disease. ER stress elicits the unfolded protein response (UPR), whose components attenuate protein synthesis, increase folding capacity, and enhance misfolded protein degradation. Here, we report that P58(IPK)/DNAJC3, a UPR-responsive gene previously implicated in translational control, encodes a cytosolic cochaperone that associates with the ER protein translocation channel Sec61. P58(IPK) recruits HSP70 chaperones to the cytosolic face of Sec61 and can be crosslinked to proteins entering the ER that are delayed at the translocon. Proteasome-mediated cytosolic degradation of translocating proteins delayed at Sec61 is cochaperone dependent. In P58(IPK-/-) mice, cells with a high secretory burden are markedly compromised in their ability to cope with ER stress. Thus, P58(IPK) is a key mediator of cotranslocational ER protein degradation, and this process likely contributes to ER homeostasis in stressed cells.
Mesh Headings (Keywords): Animals, Blood Glucose, Caenorhabditis elegans, Cells, Cultured, Diabetes Mellitus, Endoplasmic Reticulum, Female, HSP40 Heat-Shock Proteins, HSP70 Heat-Shock Proteins, Hepatocytes, Humans, Insulin, Male, Membrane Proteins, Mice, Mice, Knockout, Mice, Transgenic, Molecular Chaperones, Pancreas, Protein Transport, Vascular Cell Adhesion Molecule-1, eIF-2 Kinase
Check for Full Text / PubMed Unique Identifier (PMID): 16923392
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The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.