ATP13A2/PARK9 regulates endo-/lysosomal cargo sorting and proteostasis through a novel PI(3, 5)P2-mediated scaffolding function.
ATP13A2 (also called PARK9), is a transmembrane endo-/lysosomal-associated P5 type transport ATPase. Loss-of-function mutations in ATP13A2 result in the Kufor-Rakeb Syndrome (KRS), a form of autosomal Parkinson's disease (PD). In spite of a growing interest in ATP13A2, very little is known about its physiological role in stressed cells. Recent studies suggest that the N-terminal domain of ATP13A2 may hold key regulatory functions, but their nature remains incompletely understood. To this end, we generated a set of melanoma and neuroblastoma cell lines stably overexpressing wild-type (WT), catalytically inactive (D508N) and N-terminal mutants, or shRNA against ATP13A2. We found that under proteotoxic stress conditions, evoked by the proteasome inhibitor Bortezomib, endo-/lysosomal associated full-length ATP13A2 WT, catalytically-inactive or N-terminal fragment mutants, reduced the intracellular accumulation of ubiquitin-conjugated (Ub) proteins, independent of autophagic degradation. In contrast, ATP13A2 silencing increased the intracellular accumulation of Ub-proteins, a pattern also observed in patient-derived fibroblasts harbouring ATP13A2 loss-of function mutations. In treated cells, ATP13A2 evoked endocytic vesicle relocation and increased cargo export through nanovesicles. Expression of an ATP13A2 mutant abrogating PI(3,5)P2 binding or chemical inhibition of the PI(3,5)P2-generating enzyme PIKfyve, compromised vesicular trafficking/nanovesicles export and rescued intracellular accumulation of Ub-proteins in response to proteasomal inhibition. Hence, our study unravels a novel activity-independent scaffolding role of ATP13A2 in trafficking/export of intracellular cargo in response to proteotoxic stress.
Laboratory for Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven).
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Demirsoy
Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium.
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Martin
Laboratory for Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven).
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Motamedi
Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium.
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van Veen
Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium.
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Holemans
Research Group for Neurobiology and Gene Therapy, Department of Neurosciences, University of Leuven (KU Leuven), B3000 Leuven, Belgium.
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Van den Haute
Molecular Neurogenomics Group, VIB Center for Molecular Neurology, University of Antwerp, 2610 Antwerpen, Belgium.|Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical University-Sofia, 1431 Sofia, Bulgaria.
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Jordanova
Research Group for Neurobiology and Gene Therapy, Department of Neurosciences, University of Leuven (KU Leuven), B3000 Leuven, Belgium.
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Baekelandt
Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N1, Herestraat 49, Box 802, B-3000 Leuven, Belgium.
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Vangheluwe
Laboratory for Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven).
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Agostinis
D001343:Autophagy; D045744:Cell Line, Tumor; D011992:Endosomes / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D009154:Mutation; D010300:Parkinson Disease / Q000235:genetics / Q000378:metabolism; D020734:Parkinsonian Disorders / Q000235:genetics / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D021381:Protein Transport; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013312:Stress, Physiological
C514983:ATP13A2 protein, human; D018129:Phosphatidylinositol Phosphates; C106336:phosphatidylinositol 3,5-diphosphate; D006180:Proton-Translocating ATPases