Niemann-Pick C2 protein regulates sterol transport between plasma membrane and late endosomes in human fibroblasts

摘要: Abstract Niemann-Pick disease type C2 is a lipid storage disorder in which mutations the NPC2 protein cause accumulation of lipoprotein-derived cholesterol late endosomes and lysosomes (LE/LYSs). Whether delivered by other means to deficient cells also accumulates LE/LYSs currently unknown. We show that close analog dehydroergosterol (DHE), when plasma membrane (PM) human fibroblasts lacking functional NPC2. measured two different time scales sterol diffusion; while DHE rich moved slow anomalous diffusion (D ∼ 4.6∙10−4 μm2/sec; α∼0.76), small pool could exchange rapidly with D ∼ 3 μm2/s between LE/LYSs, as shown fluorescence recovery after photobleaching (FRAP). By quantitative mass spectrometry we found esterification 13C-labeled but not reduced 10-fold compared control cells. Internalized rescued phenotype strongly expanded dynamic seen FRAP experiments. Together, our study shows trafficking sterols PM depends on protein. likely acts inside from where it increases non-vesicular organelles.