Abstract
The pathological accumulation of cholesterol is a signature feature of Niemann–Pick type C (NPC) disease, in which excessive lipid levels induce Purkinje cell death in the cerebellum. NPC1 encodes a lysosomal cholesterol-binding protein, and mutations in NPC1 drive cholesterol accumulation in late endosomes and lysosomes (LE/Ls). However, the fundamental role of NPC proteins in LE/L cholesterol transport remains unclear. Here, we demonstrate that NPC1 mutations impair the projection of cholesterol-containing membrane tubules from the surface of LE/Ls. A proteomic survey of purified LE/Ls identified StARD9 as a novel lysosomal kinesin responsible for LE/L tubulation. StARD9 contains an N-terminal kinesin domain, a C-terminal StART domain, and a dileucine signal shared with other lysosome-associated membrane proteins. Depletion of StARD9 disrupts LE/L tubulation, paralyzes bidirectional LE/L motility and induces accumulation of cholesterol in LE/Ls. Finally, a novel StARD9 knock-out mouse recapitulates the progressive loss of Purkinje cells in the cerebellum. Together, these studies identify StARD9 as a microtubule motor protein responsible for LE/L tubulation and provide support for a novel model of LE/L cholesterol transport that becomes impaired in NPC disease.
| Original language | English (US) |
|---|---|
| Article number | jcs260662 |
| Journal | Journal of cell science |
| Volume | 136 |
| Issue number | 5 |
| DOIs | |
| State | Published - Mar 2023 |
Bibliographical note
Funding Information:The authors thank Holly Goodson and Michelle Whaley (University of Notre Dame) for input and suggestions during the course of this work. The authors thank Kostantin Dobrenis (Albert Einstein University) for providing anti-GM2 antibodies for tissue section staining, Jeff Schorey (University of Notre Dame) for providing mouse macrophage cell lines and Rossella De Cegli and Andrea Ballabio (Telethon Institute of Genetics and Medicine, Napoli, Italy) for analyzing the STARD9 gene for Coordinated Lysosomal Expression and Regulation (CLEAR) elements. The authors thank Cristin Davidson and members of the Walkley laboratory (Albert Einstein University) for help with cerebellum tissue staining and T.Y. Chang (Dartmouth University), Matthew Scott (Stanford University), Suzanne Pfeffer (Stanford University) and Michael Overholzer (Memorial Sloan Kettering Cancer Center) for FP-tagged expression constructs. The authors acknowledge the support of the Indiana Clinical and Translational Sciences Institute and Judy Hallett (Purdue University) for generation of StARD9(−/−) mice in collaboration with the Purdue University Transgenic Core Facility. We acknowledge support for this project by the University of Notre Dame Proteomics and Mass Spectrometry Facility and the Notre Dame Integrated Imaging Facility.
Funding Information:
This work was supported by funding by the Ara Parseghian Medical Research Fund, Niemann-Pick Canada and the Center for Rare and Neglected Diseases (University of Notre Dame). F.R.S. acknowledges a Schmitt Graduate Fellowship (University of Notre Dame). J.D. acknowledges a National Science Foundation-Graduate Research Fellowship Program (NSF-GRFP) fellowship. A.M.B. was a National Science Foundation-Research Experiences for Undergraduates (NSF-REU) Fellow and acknowledges additional support from the College of Science Summer Undergraduate Research Fellowship (COS-SURF) Program (University of Notre Dame) and the Clare Booth Luce Program by the Henry Luce Foundation.
Publisher Copyright:
© 2023. Published by The Company of Biologists Ltd.
Keywords
- Cholesterol
- Kinesin
- Lysosome
- Membrane tubulation
- Niemann–Pick type C disease
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.