Dataset Information

Misfolded SOD1 binds the ubiquitin ligase TRAF6

ABSTRACT: Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the selective loss of motor neurons. Mutations in Cu/Zn superoxide dismutase (SOD1) are the second most common cause of ALS and it is now well accepted that they result in a gain of toxicity due to protein misfolding. We previously demonstrated in the SOD1G93A rat model that misfolded SOD1 exists as distinct conformers and deposits on mitochondrial subpopulations. Here, using SOD1G93A rats coupled with conformation-restricted antibodies for misfolded SOD1 (AMF7-63 and B8H10), we identified the interactomes of the mitochondrial pools of misfolded SOD1. This strategy identified binding partners that uniquely interacted with either AMF7-63- or B8H10-reactive SOD1 conformers as well as a high proportion of interactors common to both conformers. Of this latter set, we identified the E3 ubiquitin ligase TNF receptor-associated factor 6 (TRAF6) and determined that exposure of the SOD1 functional loops facilitates this interaction. However, this conformational criterion is not universally fulfilled by all SOD1 mutants and differentiates TRAF6-interacting from non-interacting SOD1 mutants. Functionally, TRAF6 stimulates mutant SOD1 polyubiquitination and aggregation. While TRAF6 E3 ubiquitin ligase activity is required for the former, it is dispensable for the latter, indicating that the polyubiquitination and aggregation of mutant SOD1 mediated by TRAF6 are independent events. We propose that misfolded SOD1 binding to TRAF6 may be relevant to ALS disease.

INSTRUMENT(S): LTQ

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Brain

SUBMITTER: Arsalan Haqqani

LAB HEAD: Arsalan Haqqani

PROVIDER: PXD015279 | Pride | 2020-02-24

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	F143763.B8H10.R1.dat-pride.pride.mgf.gz	Mgf
	F143763.B8H10.R1.dat-pride.pride.mztab.gz	Mztab
	F143763.B8H10.R1.dat-pride.xml.gz	Xml
	F143764.mIgG.R1.dat-pride.pride.mgf.gz	Mgf
	F143764.mIgG.R1.dat-pride.pride.mztab.gz	Mztab

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Publications

TNF receptor-associated factor 6 interacts with ALS-linked misfolded superoxide dismutase 1 and promotes aggregation.

Semmler Sabrina S Gagné Myriam M Garg Pranav P Pickles Sarah R SR Baudouin Charlotte C Hamon-Keromen Emeline E Destroismaisons Laurie L Khalfallah Yousra Y Chaineau Mathilde M Caron Elise E Bayne Andrew N AN Trempe Jean-François JF Cashman Neil R NR Star Alexandra T AT Haqqani Arsalan S AS Durcan Thomas M TM Meiering Elizabeth M EM Robertson Janice J Grandvaux Nathalie N Plotkin Steven S SS McBride Heidi M HM Vande Velde Christine C

The Journal of biological chemistry 20200206 12

Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the selective loss of motor neurons leading to paralysis. Mutations in the gene encoding superoxide dismutase 1 (SOD1) are the second most common cause of familial ALS, and considerable evidence suggests that these mutations result in an increase in toxicity due to protein misfolding. We previously demonstrated in the SOD1<sup>G93A</sup> rat model that misfolded SOD1 exists as distinct conformers and forms deposits on mitoc ...[more]

PMID: 32029478

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Project description:Familial amyotrophic lateral sclerosis (ALS) represents about 10% of ALS cases. In about 20% of familial ALS patients, a mutation in superoxide dismutase-1 (SOD1) can be found. The ubiquitous SOD1 protein converts superoxide radical anions to oxygen and hydrogen peroxide. Patients with familial ALS caused by mutations in SOD1 can show comorbidity with frontotemporal dementia and develop cognitive impairment, including apathy, inattention, verbal deficits, and hypersexuality. At the cellular level, pathological signs of ALS may include tau immunoreactive astrocytic and neuronal inclusions, suggesting that cognitive dysfunction in ALS may also reflect abnormal protein metabolism of the microtubule associated protein (MAP), tau. To identify cell-specific expression changes, we performed laser capture microdissection (LCM) to isolate anterior horn motor neurons and surrounding cells. To determine common pathways for the development of ALS due to dysfunction of SOD1 or TAU, we performed whole transcriptome analysis in SOD1 and TAU mouse models. Because ALS is a neurodegenerative disease that specifically affects motor neurons, these cells were the main investigative target. Global transcriptomes of glial cells surrounding the motor neurons were also assessed, because these cells have been implicated as triggers of neurodegeneration. Mouse experiments were performed at the presymptomatic stage, prior to the onset of cell loss, in order to reduce false positive signals due to tissue reactive changes. Lumbar anterior horn anterior horn motor neurons and surrounding cells (glia) were isolated from presymptomatic TAU-P301L and SOD1-G93A transgenic mice using laser capture microdissection (LCM; PixCellÂ® IIe LCM System, Arcturus, Molecular Devices, CA). On average, 500 motor neuron bodies or surrounding glial cells from 20 tissue sections per animal were collected. RNA isolation from LCM collected cells was performed using the Qiagen RNeasy Micro Kit. Only RNA with RNA Integrity Numbers (RIN) above 7.5 were taken for further analysis (Agilent Bioanalyzer 2100). A two-round T7-based amplification and labeling protocol (Agilent Low RNA Input Linear Amplification Kit PLUS) was used to generate high quality labeled cRNA. Agilent Whole Mouse Genome Microarray comparisons of motor neurons and surrounding glia were performed between transgenic (SOD1G93A and TAUP301L) and corresponding nontransgenic (control) littermate animals, producing four independent comparison groups: SOD1G93A motor neurons versus control motor neurons (SOD1mn), SOD1G93A motor neuron surrounding glia versus control glia (SOD1gl), TAUP301L motor neurons versus control motor neurons (TAUmn) and TAUP301L glia versus control glia (TAUgl). Each comparison used four pairs of transgenic (SOD1G93A or TAUP301L) vs. corresponding control littermate animals, producing four biological replicates. Raw microarray data were acquired using the Agilent DNA Microarray scanner and processed with the accompanying Agilent Feature Extraction 10.5 Image Analysis software using default settings. Normalized signal intensities were used to identify gene expression changes in SOD1G93A and TAUP301L motor neurons and surrounding glial cells, generating four partially overlapping sets of data. For the identification of differential expression, the genes were required to pass two conservative criteria: a ratio beyond the 99.5% confidence interval observed in homotypic comparisons, which corresponded to an approximately 1.5-fold expression change, and a paired t-test (P<0.01) computed using 100 permutations of the data for each gene. Correction for multiple comparisons was performed using the adjusted Bonferroni test. The analysis was performed in the TM4: Microarray Software Suite. These techniques identified 251 transcripts representing 186 known genes for which expression was altered in at least one of the four comparisons. Four-condition experiment, SOD1G93A motor neurons versus control motor neurons (SODmn), SOD1G93A motor neuron surrounding glia versus control glia (SODgl), TAUP301L motor neurons versus control motor neurons (TAUmn) and TAUP301L glia versus control glia (TAUgl). Each comparison used four pairs of transgenic (SOD1G93A or TAUP301L) vs. corresponding control littermate animals, producing four biological replicates. Biological replicates: 4 SOD1G93A motor neurons (SODmn), 4 non SOD littermate motor neurons (nonSODmn), 4 SOD1G93A motor neuron surrounding glia (SODgl), 4 non SOD littermate motor neuron surrounding glia (nonSODgl), 4 TAUP301L motor neurons (TAUmn), 4 non TAU littermate motor neurons (nonTAUmn), 4 TAUP301L motor neuron surrounding glia (TAUgl), 4 non TAU littermate motor neuron surrounding glia (nonTAUgl). Four independent comparison groups were generated: SOD1G93A motor neurons versus control nonSOD motor neurons, SOD1G93A motor neuron surrounding glia versus control nonSOD glia, TAUP301L motor neurons versus control nonTAU motor neurons and TAUP301L glia versus control nonTAU glia. Each comparison used four pairs of transgenic (SOD1G93A or TAUP301L) vs. corresponding control littermate animals, producing four biological replicates. Each replicate was repeated twice with dye flip to correct for unequal dye incorporation rates. Therefore, eight microarray hybridizations were performed for each biological comparison, for a total of 32 microarray slides and generating four groups of differentially expressed genes in SOD1G93A motor neurons (SODmn), SOD1G93A motor neuron surrounding glial cells (SODgl), TAUP301L motor neurons (TAUmn), and TAUP301L surrounding glial cells (TAUgl).