Wolfram syndrome 1 gene negatively regulates ER stress signaling in rodent and human cells
Fonseca, Sonya G. ; Ishigaki, Shinsuke ; Oslowski, Christine M. ; Lu, Simin ; Lipson, Kathryn L. ; Ghosh, Rajarshi ; Hayashi, Emiko ; Ishihara, Hisamitsu ; Oka, Yoshitomo ; Permutt, M. Alan ... show 1 more
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Faculty Advisor
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UMass Chan Affiliations
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Keywords
Animals
COS Cells
Calmodulin-Binding Proteins
Cell Line, Tumor
Cercopithecus aethiops
Endoplasmic Reticulum
Gene Expression Regulation
Humans
Insulin-Secreting Cells
Membrane Proteins
Mice
Proteasome Endopeptidase Complex
Rats
Signal Transduction
Trans-Activators
Ubiquitin
Ubiquitin-Protein Ligases
Ubiquitination
Unfolded Protein Response
Wolfram Syndrome
Genetics and Genomics
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Abstract
Wolfram syndrome is an autosomal-recessive disorder characterized by insulin-dependent diabetes mellitus, caused by nonautoimmune loss of beta cells, and neurological dysfunctions. We have previously shown that mutations in the Wolfram syndrome 1 (WFS1) gene cause Wolfram syndrome and that WFS1 has a protective function against ER stress. However, it remained to be determined how WFS1 mitigates ER stress. Here we have shown in rodent and human cell lines that WFS1 negatively regulates a key transcription factor involved in ER stress signaling, activating transcription factor 6alpha (ATF6alpha), through the ubiquitin-proteasome pathway. WFS1 suppressed expression of ATF6alpha target genes and repressed ATF6alpha-mediated activation of the ER stress response element (ERSE) promoter. Moreover, WFS1 stabilized the E3 ubiquitin ligase HRD1, brought ATF6alpha to the proteasome, and enhanced its ubiquitination and proteasome-mediated degradation, leading to suppression of ER stress signaling. Consistent with these data, beta cells from WFS1-deficient mice and lymphocytes from patients with Wolfram syndrome exhibited dysregulated ER stress signaling through upregulation of ATF6alpha and downregulation of HRD1. These results reveal a role for WFS1 in the negative regulation of ER stress signaling and in the pathogenesis of diseases involving chronic, unresolvable ER stress, such as pancreatic beta cell death in diabetes.
Source
Published in Volume 120, Issue 3 (March 1, 2010). J Clin Invest. 2010;120(3):744–755. doi:10.1172/JCI39678.