State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; College of Life Sciences, the Institute for Advanced Studies, Wuhan University, Wuhan 430072, China; College of Animal Sciences and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan Province, China.
State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Cell. 2015 Apr 9;161(2):291-306. doi: 10.1016/j.cell.2015.02.019.
Cholesterol is dynamically transported among organelles, which is essential for multiple cellular functions. However, the mechanism underlying intracellular cholesterol transport has remained largely unknown. We established an amphotericin B-based assay enabling a genome-wide shRNA screen for delayed LDL-cholesterol transport and identified 341 hits with particular enrichment of peroxisome genes, suggesting a previously unappreciated pathway for cholesterol transport. We show dynamic membrane contacts between peroxisome and lysosome, which are mediated by lysosomal Synaptotagmin VII binding to the lipid PI(4,5)P2 on peroxisomal membrane. LDL-cholesterol enhances such contacts, and cholesterol is transported from lysosome to peroxisome. Disruption of critical peroxisome genes leads to cholesterol accumulation in lysosome. Together, these findings reveal an unexpected role of peroxisome in intracellular cholesterol transport. We further demonstrate massive cholesterol accumulation in human patient cells and mouse model of peroxisomal disorders, suggesting a contribution of abnormal cholesterol accumulation to these diseases.
胆固醇在细胞器之间动态运输,这对多种细胞功能至关重要。然而,细胞内胆固醇运输的机制在很大程度上仍然未知。我们建立了一种基于两性霉素 B 的测定法,可进行针对 LDL-胆固醇运输延迟的全基因组 shRNA 筛选,并鉴定出 341 个与过氧化物酶体基因特别富集的命中,这表明胆固醇运输存在以前未被认识的途径。我们显示了过氧化物酶体和溶酶体之间的动态膜接触,这是由溶酶体突触结合蛋白 VII 与过氧化物酶体膜上的脂质 PI(4,5)P2 结合介导的。LDL-胆固醇增强了这种接触,胆固醇从溶酶体转运到过氧化物酶体。破坏关键的过氧化物酶体基因会导致胆固醇在溶酶体中积累。总之,这些发现揭示了过氧化物体在细胞内胆固醇运输中的意外作用。我们进一步证明了人类患者细胞和过氧化物酶体疾病小鼠模型中大量胆固醇的积累,这表明异常胆固醇积累对这些疾病有一定的影响。