{Reference Type}: Journal Article
{Title}: StARD9 is a novel lysosomal kinesin required for membrane tubulation, cholesterol transport and Purkinje cell survival.
{Author}: Sterling FR;D'Amico J;Brumfield AM;Huegel KL;Vaughan PS;Morris K;Schwarz S;Joyce MV;Boggess B;Champion MM;Maciuba K;Allen P;Marasco E;Koch G;Gonzalez P;Hodges S;Leahy S;Gerstbauer E;Hinchcliffe EH;Vaughan KT;
{Journal}: J Cell Sci
{Volume}: 136
{Issue}: 5
{Year}: 03 2023 1
{Factor}: 5.235
{DOI}: 10.1242/jcs.260662
{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.