2. Academic Validation
  3. Cholesterol transfer via endoplasmic reticulum contacts mediates lysosome damage repair

Cholesterol transfer via endoplasmic reticulum contacts mediates lysosome damage repair

  • EMBO J. 2022 Nov 21;e112677. doi: 10.15252/embj.2022112677.
Maja Radulovic 1 2,  Eva Maria Wenzel 1 2,  Sania Gilani 1 2,  Lya Kk Holland 3,  Alf Håkon Lystad 1 2,  Santosh Phuyal 1 4,  Vesa M Olkkonen 5 6,  Andreas Brech 1 2,  Marja Jäättelä 3 7,  Kenji Maeda 3,  Camilla Raiborg 1 2,  Harald Stenmark 1 2
Affiliations

Affiliations

  • 1 Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway.
  • 2 Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
  • 3 Cell Death and Metabolism, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark.
  • 4 Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
  • 5 Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland.
  • 6 Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
  • 7 Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
PMID: 36408828 DOI: 10.15252/embj.2022112677
Abstract

Lysosome integrity is essential for cell viability, and lesions in lysosome membranes are repaired by the ESCRT machinery. Here, we describe an additional mechanism for lysosome repair that is activated independently of ESCRT recruitment. Lipidomic analyses showed increases in lysosomal phosphatidylserine and Cholesterol after damage. Electron microscopy demonstrated that lysosomal membrane damage is rapidly followed by the formation of contacts with the endoplasmic reticulum (ER), which depends on the ER proteins VAPA/B. The cholesterol-binding protein ORP1L was recruited to damaged lysosomes, accompanied by Cholesterol accumulation by a mechanism that required VAP-ORP1L interactions. The PtdIns 4-kinase PI4K2A rapidly produced PtdIns4P on lysosomes upon damage, and knockout of PI4K2A inhibited damage-induced accumulation of ORP1L and Cholesterol and led to the failure of lysosomal membrane repair. The cholesterol-PtdIns4P transporter OSBP was also recruited upon damage, and its depletion caused lysosomal accumulation of PtdIns4P and resulted in cell death. We conclude that ER contacts are activated on damaged lysosomes in parallel to ESCRTs to provide lipids for membrane repair, and that PtdIns4P generation and removal are central in this response.

Keywords

cholesterol; lysosome; membrane contact site; membrane repair; phosphoinositide.

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