title: ALS-associated mutant FUS inhibits macroautophagy which is restored by overexpression of Rab1.
abstract: Amyotrophic lateral sclerosis (ALS) is characterised by the formation of intracellular misfolded protein inclusions that form in motor neurons. Autophagy is the major degradation pathway for aggregate-prone proteins within lysosomes. Autophagy begins by the production of the omegasome, forming the autophagosome membrane, which then fuses with the lysosome. Mutations in fused in sarcoma (FUS) cause 5% of familial ALS cases and FUS-positive inclusions are also formed in sporadic ALS tissues. In this study, we demonstrate that the expression of ALS-associated mutant FUS impairs autophagy in neuronal cells. In mutant FUS-expressing neuronal cells, accumulation of ubiquitinated proteins and autophagy substrates p62 and NBR1 was detected, and formation of both the omegasome and autophagosome was inhibited in these cells. However, overexpression of Rab1 rescued these defects, suggesting that Rab1 is protective in ALS. The number of LC3-positive vesicles was also increased in motor neurons from the spinal cord of an ALS patient carrying a FUS (R521C) mutation compared with a control patient, providing additional evidence that autophagy is dysregulated in mutant FUS-associated ALS. This study provides further understanding of the intricate autophagy system and neurodegeneration in ALS.
authors.affiliation: Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University , Bundoora, Victoria, Australia.
authors.forename: K Y
authors.initials: KY
authors.lastname: Soo
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University , North Ryde, New South Wales, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Sultana
authors.affiliation: Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, Tasmania, Australia.
authors.forename: A E
authors.initials: AE
authors.lastname: King
authors.affiliation: Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, Tasmania, Australia.
authors.forename: Rak
authors.initials: R
authors.lastname: Atkinson
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University , North Ryde, New South Wales, Australia.
authors.forename: S T
authors.initials: ST
authors.lastname: Warraich
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University , North Ryde, New South Wales, Australia.
authors.forename: V
authors.initials: V
authors.lastname: Sundaramoorthy
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University , North Ryde, New South Wales, Australia.
authors.forename: I
authors.initials: I
authors.lastname: Blair
authors.affiliation: Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University , Bundoora, Victoria, Australia.
authors.forename: M A
authors.initials: MA
authors.lastname: Farg
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University , North Ryde, New South Wales, Australia.
authors.forename: J D
authors.initials: JD
authors.lastname: Atkin