Dataset Information

Membrane aberrancy and unfolded proteins activate the endoplasmic reticulum stress sensor Ire1 in different ways.

ABSTRACT: Eukaryotic cells activate the unfolded-protein response (UPR) upon endoplasmic reticulum (ER) stress, where the stress is assumed to be the accumulation of unfolded proteins in the ER. Consistent with previous in vitro studies of the ER-luminal domain of the mutant UPR initiator Ire1, our study show its association with a model unfolded protein in yeast cells. An Ire1 luminal domain mutation that compromises Ire1's unfolded-protein-associating ability weakens its ability to respond to stress stimuli, likely resulting in the accumulation of unfolded proteins in the ER. In contrast, this mutant was activated like wild-type Ire1 by depletion of the membrane lipid component inositol or by deletion of genes involved in lipid homeostasis. Another Ire1 mutant lacking the authentic luminal domain was up-regulated by inositol depletion as strongly as wild-type Ire1. We therefore conclude that the cytosolic (or transmembrane) domain of Ire1 senses membrane aberrancy, while, as proposed previously, unfolded proteins accumulating in the ER interact with and activate Ire1.

SUBMITTER: Promlek T

PROVIDER: S-EPMC3172275 | biostudies-other | 2011 Sep

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Membrane aberrancy and unfolded proteins activate the endoplasmic reticulum stress sensor Ire1 in different ways.

Promlek Thanyarat T Ishiwata-Kimata Yuki Y Shido Masahiro M Sakuramoto Mitsuru M Kohno Kenji K Kimata Yukio Y

Molecular biology of the cell 20110720 18

Eukaryotic cells activate the unfolded-protein response (UPR) upon endoplasmic reticulum (ER) stress, where the stress is assumed to be the accumulation of unfolded proteins in the ER. Consistent with previous in vitro studies of the ER-luminal domain of the mutant UPR initiator Ire1, our study show its association with a model unfolded protein in yeast cells. An Ire1 luminal domain mutation that compromises Ire1's unfolded-protein-associating ability weakens its ability to respond to stress sti ...[more]

PMID: 21775630

Similar Datasets

Project description:The unfolded-protein response (UPR) is a signal transduction cascade triggered by perturbation of the homeostasis of the endoplasmic reticulum (ER). UPR resolves ER stress by activating a cascade of cellular responses, including the induction of molecular chaperones, translational attenuation, ER-associated degradation, and other mechanisms. Under prolonged and irremediable ER stress, however, the UPR can also trigger apoptosis. Here, we report that in cells infected with the avian coronavirus infectious bronchitis virus (IBV), ER stress was induced and the IRE1?-XBP1 pathway of UPR was activated. Knockdown and overexpression experiments demonstrated that IRE1? protects infected cells from IBV-induced apoptosis, which required both its kinase and RNase activities. Our data also suggest that splicing of XBP1 mRNA by IRE1? appears to convert XBP1 from a proapoptotic XBP1u protein to a prosurvival XBP1s protein. Moreover, IRE1? antagonized IBV-induced apoptosis by modulating the phosphorylation status of the proapoptotic c-Jun N-terminal kinase (JNK) and the prosurvival RAC-alpha serine/threonine-protein kinase (Akt). Taken together, the data indicate that the ER stress sensor IRE1? is activated in IBV-infected cells and serves as a survival factor during coronavirus infection.Animal coronaviruses are important veterinary viruses, which could cross the species barrier, becoming severe human pathogens. Molecular characterization of the interactions between coronaviruses and host cells is pivotal to understanding the pathogenicity and species specificity of coronavirus infection. It has been well established that the endoplasmic reticulum (ER) is closely associated with coronavirus replication. Here, we report that inositol-requiring protein 1 alpha (IRE1?), a key sensor of ER stress, is activated in cells infected with the avian coronavirus infectious bronchitis virus (IBV). Moreover, IRE1? is shown to protect the infected cells from apoptosis by modulating the unfolded-protein response (UPR) and two kinases related to cell survival. This study demonstrates that UPR activation constitutes a major aspect of coronavirus-host interactions. Manipulations of the coronavirus-induced UPR may provide novel therapeutic targets for the control of coronavirus infection and pathogenesis.

Dataset Information

Membrane aberrancy and unfolded proteins activate the endoplasmic reticulum stress sensor Ire1 in different ways.

Publications

Membrane aberrancy and unfolded proteins activate the endoplasmic reticulum stress sensor Ire1 in different ways.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets