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Cell Death Dis. 2014 Jan 9;5:e989. doi: 10.1038/cddis.2013.522.

JNK interaction with Sab mediates ER stress induced inhibition of mitochondrial respiration and cell death.

Author information

1
Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California Research Center for Liver Diseases, University of Southern California, Los Angeles, CA 90089-9121, USA.
2
1] Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California Research Center for Liver Diseases, University of Southern California, Los Angeles, CA 90089-9121, USA [2] Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA [3] Department of Cell Death and Proliferation, Institute of Biomedical Research of Barcelona (IIBB), Consejo Superior Investigaciones Cientificas (CSIC) and Liver Unit-Hospital Clinic and CIBEREHD, Barcelona, Spain.
3
1] Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University of Southern California Research Center for Liver Diseases, University of Southern California, Los Angeles, CA 90089-9121, USA [2] Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.

Abstract

Our aim was to better understand the mechanism and importance of sustained c-Jun N-terminal kinase (JNK) activation in endoplasmic reticulum (ER) stress and effects of ER stress on mitochondria by determining the role of mitochondrial JNK binding protein, Sab. Tunicamycin or brefeldin A induced a rapid and marked decline in basal mitochondrial respiration and reserve-capacity followed by delayed mitochondrial-mediated apoptosis. Knockdown of mitochondrial Sab prevented ER stress-induced sustained JNK activation, impaired respiration, and apoptosis, but did not alter the magnitude or time course of activation of ER stress pathways. P-JNK plus adenosine 5'-triphosphate (ATP) added to isolated liver mitochondria promoted superoxide production, which was amplified by addition of calcium and inhibited by a blocking peptide corresponding to the JNK binding site on Sab (KIM1). This peptide also blocked tunicamycin-induced inhibition of cellular respiration. In conclusion, ER stress triggers an interaction of JNK with mitochondrial Sab, which leads to impaired respiration and increased mitochondrial reactive oxygen species, sustaining JNK activation culminating in apoptosis.

PMID:
24407242
PMCID:
PMC4040675
DOI:
10.1038/cddis.2013.522
[Indexed for MEDLINE]
Free PMC Article

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