Journal article
The ubiquitin ligase F-box/G-domain protein 1 promotes the degradation of the disease-linked protein torsinA through the ubiquitin–proteasome pathway and macroautophagy
Neuroscience, Vol.224, pp.160-171
11/08/2012
DOI: 10.1016/j.neuroscience.2012.08.023
PMID: 22917612
Abstract
► FBG1 promotes torsinA degradation. ► FBG1 acts through both the proteasome and autophagy. ► The N-terminal domain of FBG1 is key for its functional versatility. ► Absence of FBG1 triggers age-related motor dysfunction in torsinA(ΔE) knock-in mice.
DYT1 dystonia is a dominantly inherited, disabling neurological disorder with low penetrance that is caused by the deletion of a glutamic acid (ΔE) in the protein torsinA. We previously showed that torsinA(wt) is degraded through macroautophagy while torsinA(ΔE) is targeted to the ubiquitin–proteasome pathway (UPP). The different catabolism of torsinA(wt) and (ΔE) potentially modulates torsinA(wt):torsinA(ΔE) stoichiometry. Therefore, gaining a mechanistic understanding on how the protein quality control machinery clears torsinA(ΔE) in neurons may uncover important regulatory steps in disease pathogenesis. Here, we asked whether F-box/G-domain protein 1 (FBG1), a ubiquitin ligase known to degrade neuronal glycoproteins, is implicated in the degradation of torsinA(ΔE) by the UPP. In a first set of studies completed in cultured cells, we show that FBG1 interacts with and influences the steady-state levels of torsinA(wt) and (ΔE). Interestingly, FBG1 achieves this effect promoting the degradation of torsinA not only through the UPP, but also by macroautophagy. To determine the potential clinical significance of these findings, we asked if eliminating expression of Fbg1 triggers a motor phenotype in torsinA(ΔE) knock in (KI) mice, a model of non-manifesting DYT1 mutation carriers. We detected differences in spontaneous locomotion between aged torsinA(ΔE) KI–Fbg1 knock out and control mice. Furthermore, neuronal levels of torsinA were unaltered in Fbg1 null mice, indicating that redundant systems likely compensate in vivo for the absence of this ubiquitin ligase. In summary, our studies support a non-essential role for FBG1 on the degradation of torsinA and uncover a novel link of FBG1 to the autophagy pathway.
Details
- Title: Subtitle
- The ubiquitin ligase F-box/G-domain protein 1 promotes the degradation of the disease-linked protein torsinA through the ubiquitin–proteasome pathway and macroautophagy
- Creators
- K.L Gordon - Graduate Program of Neuroscience, University of Iowa, Iowa City, IA 52242, USAK.A Glenn - Veterans Administration Hospital, Iowa City, IA 52242, USAN Bode - Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAH.M Wen - Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USAH.L Paulson - Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USAP Gonzalez-Alegre - Graduate Program of Neuroscience, University of Iowa, Iowa City, IA 52242, USA
- Resource Type
- Journal article
- Publication Details
- Neuroscience, Vol.224, pp.160-171
- DOI
- 10.1016/j.neuroscience.2012.08.023
- PMID
- 22917612
- NLM abbreviation
- Neuroscience
- ISSN
- 0306-4522
- eISSN
- 1873-7544
- Publisher
- Elsevier Ltd
- Grant note
- name: NIH, award: K02NS058450, F31NS073348, R01AG034228; name: VA Research Career Development Award
- Language
- English
- Date published
- 11/08/2012
- Academic Unit
- Psychiatry; General Internal Medicine; Internal Medicine
- Record Identifier
- 9984094498902771
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