Dynamic movements of organelles containing Niemann-Pick C1 protein: NPC1 involvement in late endocytic events
Dynamic movements of organelles containing Niemann-Pick C1 protein: NPC1 involvement in late endocytic events
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DOI：
10.1091/mbc.12.3.601
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发表时间：
2001-03-01
影响因子：
3.3
通讯作者：
Scott, MP
中科院分区：
文献类型：
--
作者：
Ko, DC;Gordon, MD;Scott, MP
Niemann-Pick C1型(NPC1)基因突变纯合子的人有生理缺陷，包括细胞内胆固醇和其他脂质的过度积累，导致神经和肝脏的剧烈退化。NPC1多通道跨膜蛋白存在于晚期内吞体内和溶酶体中，但其功能尚不清楚。我们发现，含有功能性NPC1-荧光蛋白融合的细胞器经历了戏剧性的移动，其中一些与内质网链的延伸有关。在NPC1突变细胞中，通常在核周区域和细胞外围之间高速移动的带有NPC1的细胞器在很大程度上缺失。二芳基碳菁类低密度脂蛋白的脉冲追逐实验表明，NPC1细胞器在内吞途径中的作用较晚；NPC1蛋白可能有助于内吞和溶酶体的分隔。NPC1和导致NPC1样细胞器缺陷的药物U18666A之间的密切联系是通过拯救过量产生NPC1的药物治疗细胞而建立的。U18666A抑制NPC1细胞器向外移动，将膜和胆固醇捕获到核周细胞器中，类似于NPC1突变细胞，即使细胞生长在脂蛋白耗竭的血清中也是如此。我们的结论是，NPC1蛋白促进特定的晚期内小体的创建和/或移动，这些内小体快速地将物质输送到细胞外围和从细胞外围传出。
People homozygous for mutations in the Niemann-Pick type C1 (NPC1) gene have physiological defects, including excess accumulation of intracellular cholesterol and other lipids, that lead to drastic neural and liver degeneration. The NPC1 multipass transmembrane protein is resident in late endosomes and lysosomes, but its functions are unknown. We find that organelles containing functional NPC1-fluorescent protein fusions undergo dramatic movements, some in association with extending strands of endoplasmic reticulum. In NPC1 mutant cells the NPC1-bearing organelles that normally move at high speed between perinuclear regions and the periphery of the cell are largely absent. Pulse-chase experiments with dialkylindocarbocyanine low-density lipoprotein showed that NPC1 organelles function late in the endocytic pathway; NPC1 protein may aid the partitioning of endocytic and lysosomal compartments. The close connection between NPC1 and the drug U18666A, which causes NPC1-like organelle defects, was established by rescuing drug-treated cells with overproduced NPC1. U18666A inhibits outward movements of NPC1 organelles, trapping membranes and cholesterol in perinuclear organelles similar to those in NPC1 mutant cells, even when cells are grown in lipoprotein-depleted serum. We conclude that NPC1 protein promotes the creation and/or movement of particular late endosomes, which rapidly transport materials to and from the cell periphery.