The S349T mutation of SQSTM1 links Keap1/Nrf2 signalling to Paget's disease of bone
| Autor: | Sarah L. Rea, B. Kevin Park, Christopher E. Goldring, Jed Long, Mark S. Searle, Andrew J. Bennett, Alice Goode, Thomas Ratajczak, Tao Wright, Ian M. Copple, Robert Layfield |
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| Rok vydání: | 2013 |
| Předmět: |
Models
Molecular Sequestosome-1 Protein Histology NF-E2-Related Factor 2 Physiology Endocrinology Diabetes and Metabolism Molecular Sequence Data Mutant Protein Data Bank (RCSB PDB) Biology medicine.disease_cause Sequestosome 1 Skeletal disorder medicine Humans Amino Acid Sequence education Transcription factor Adaptor Proteins Signal Transducing Genetics education.field_of_study Mutation Kelch-Like ECH-Associated Protein 1 Ubiquitin Intracellular Signaling Peptides and Proteins NF-kappa B Osteitis Deformans KEAP1 Cell biology HEK293 Cells Amino Acid Substitution Sequence Alignment Protein Binding Signal Transduction |
| Zdroj: | Bone. 52:699-706 |
| ISSN: | 8756-3282 |
| DOI: | 10.1016/j.bone.2012.10.023 |
| Popis: | Mutations affecting the Sequestosome 1 (SQSTM1) gene commonly occur in patients with the skeletal disorder Paget's disease of bone (PDB), a condition characterised by defective osteoclast differentiation and function. Whilst most mutations cluster within the ubiquitin-associated (UBA) domain of the SQSTM1 protein, and are associated with dysregulated NFκB signalling, several non-UBA domain mutations have also been identified. Keap1 is a SQSTM1-interacting protein that regulates the levels and activity of the Nrf2 transcription factor. This in turn controls the expression of numerous cytoprotective genes that contribute to the cell's capacity to defend itself against chemical and oxidative stress, through binding to the antioxidant response element (ARE). The PDB-associated S349T mutation maps to the Keap1-interacting region (KIR) of SQSTM1, however the effects of PDB mutant SQSTM1 on Keap1 function have not been investigated. Here we show that unlike other SQSTM1 mutations, the S349T mutation results in neither impaired ubiquitin-binding function in pull-down assays, nor dysregulated NFκB signalling in luciferase reporter assays. Keap1 is expressed in differentiating osteoclast-like cells and the S349T mutation selectively impairs the SQSTM1-Keap1 interaction in co-immunoprecipitations, which molecular modelling indicates results from effects on critical hydrogen bonds required to stabilise the KIR-Keap1 complex. Further, S349T mutant SQSTM1, but not other PDB-associated mutants, showed reduced ability to activate Nrf2 signalling as assessed by ARE-luciferase reporter assays. Thus, SQSTM1-mediated dysregulation of the Keap1-Nrf2 axis, which could potentially lead to aberrant production of oxidative response genes, may contribute to disease aetiology in a subset of PDB patients. |
| Databáze: | OpenAIRE |
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