| First Author | Sterling FR | Year | 2023 |
| Journal | J Cell Sci | Volume | 136 |
| Issue | 5 | PubMed ID | 36861884 |
| Mgi Jnum | J:336775 | Mgi Id | MGI:7448673 |
| Doi | 10.1242/jcs.260662 | Citation | Sterling FR, et al. (2023) StARD9 is a novel lysosomal kinesin required for membrane tubulation, cholesterol transport and Purkinje cell survival. J Cell Sci 136(5):jcs260662 |
| abstractText | 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. |
