Seminars and Events

Past Events

Category Seminar
Date and Time 2007-02-26 16:30 - 17:00
Venue Seminar Room A7F
Speaker Xun Huang
Affiliation Institute of Genetics and Developmantal Biology, Chinese Academy of Sciences
Title Probing intracellular cholesterol trafficking: Lessons from Drosophila models of Niemann Pick type C disease
Poster click here to download(PDF)
Host Fumio Matsuzaki
Summary Cholesterol, an essential component of eukaryotic cell membranes, also serves as the precursor of many steroid hormones and thus plays vital roles in many developmental processes. Cells in the body maintain proper cholesterol levels through elegant homeostatic regulatory systems which largely depend on intracellular cholesterol trafficking. Niemann-Pick type C (NPC) disease is a cholesterol homeostasis-related neurodegenerative disorder characterized by aberrant accumulation of free cholesterol in late endosome and lysosome compartments. We have created Drosophila NPC models with npc1a and npc2 mutations. In Drosophila, npc is crucial for sterol homeostasis, as is mammalian NPC1. The fly mutants have a molting defect, and the defect can be rescued by feeding them excess ecdysone or either of two precursors of ecdysone: cholesterol and 7-dehydrocholesterol. Thus the ecdysone deficiency is evidently due to an inability to access sufficient sterol precursor, a somewhat surprising result given the massive accumulations of sterol that are seen in the mutants. The simplest explanation is that the accumulated sterol, stored as it is in multi-lamellar and multivesicular compartments, is not available for ecdysone synthesis. Our finding provides a new idea for designing treatments for NPC disease.
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