%0 Journal Article
%T StARD9 is a novel lysosomal kinesin required for membrane tubulation, cholesterol transport and Purkinje cell survival.
%A Sterling FR
%A D'Amico J
%A Brumfield AM
%A Huegel KL
%A Vaughan PS
%A Morris K
%A Schwarz S
%A Joyce MV
%A Boggess B
%A Champion MM
%A Maciuba K
%A Allen P
%A Marasco E
%A Koch G
%A Gonzalez P
%A Hodges S
%A Leahy S
%A Gerstbauer E
%A Hinchcliffe EH
%A Vaughan KT
%J J Cell Sci
%V 136
%N 5
%D 03 2023 1
%M 36861884
%F 5.235
%R 10.1242/jcs.260662
%X 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.