ATP13A2/PARK9 regulates endo-/lysosomal cargo sorting and proteostasis through a novel PI(3,5)P2-mediated scaffolding function

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Demirsoy S., Martin S., Motamedi S., van Veen S., Holemans T., Van den Haute C., ...More

HUMAN MOLECULAR GENETICS, vol.26, no.9, pp.1656-1669, 2017 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 9
  • Publication Date: 2017
  • Doi Number: 10.1093/hmg/ddx070
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1656-1669
  • Hacettepe University Affiliated: No


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.