Requirement of Myosin Vb.Rab11a.Rab11-FIP2 Complex in Cholesterol-regulated Translocation of NPC1L1 to the Cell Surface
Requirement of Myosin Vb.Rab11a.Rab11-FIP2 Complex in Cholesterol-regulated Translocation of NPC1L1 to the Cell Surface
复制标题
胆固醇调节的 NPC1L1 易位至细胞表面需要肌球蛋白 Vb.Rab11a.Rab11-FIP2 复合物
DOI：
10.1074/jbc.m109.034355
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发表时间：
2009-08-14
影响因子：
4.8
通讯作者：
Song, Bao-Liang
中科院分区：
文献类型：
--
作者：
Chu, Bei-Bei;Ge, Liang;Song, Bao-Liang
尼曼-匹克C1样1（NPC 1 L1）在游离胆固醇的肠肝吸收中起关键作用。细胞胆固醇耗竭诱导NPC 1 L1从内吞再循环区室转运至质膜（PM），胆固醇补充导致NPC 1 L1与胆固醇一起通过网格蛋白介导的内吞作用内化。虽然NPC 1 L1已被表征，但参与胆固醇吸收和NPC 1 L1的内吞再循环的其他蛋白质在很大程度上是未知的。大多数囊泡运输事件依赖于细胞骨架和马达蛋白。在这里，我们调查的微丝和microvaccent-associated三重复合物组成的肌球蛋白Vb，Rab 11 a，Rab 11-FIP 2在运输NPC 1 L1从内吞回收室PM的作用。通过药物治疗干扰微丝的动力学延迟了NPC 1 L1向细胞表面的运输。同时，肌球蛋白Vb. Rab 11 a. Rab 11-FIP 2三重复合物的任何组分的失活抑制NPC 1 L1的输出。肌球蛋白Vb、Rab 11 a或Rab 11-FIP 2的显性负突变体的表达通过阻断NPC 1 L1向PM的转运而降低细胞胆固醇摄取。这些结果表明NPC 1 L1向PM的有效转运依赖于与微生物活性相关的肌球蛋白Vb. Rab 11 a. Rab 11-FIP 2三重复合物。
Niemann-Pick C1-like 1 (NPC1L1) plays a critical role in the enterohepatic absorption of free cholesterol. Cellular cholesterol depletion induces the transport of NPC1L1 from the endocytic recycling compartment to the plasma membrane (PM), and cholesterol replenishment causes the internalization of NPC1L1 together with cholesterol via clathrin-mediated endocytosis. Although NPC1L1 has been characterized, the other proteins involved in cholesterol absorption and the endocytic recycling of NPC1L1 are largely unknown. Most of the vesicular trafficking events are dependent on the cytoskeleton and motor proteins. Here, we investigated the roles of the microfilament and microfilament-associated triple complex composed of myosin Vb, Rab11a, and Rab11-FIP2 in the transport of NPC1L1 from the endocytic recycling compartment to the PM. Interfering with the dynamics of the microfilament by pharmacological treatment delayed the transport of NPC1L1 to the cell surface. Meanwhile, inactivation of any component of the myosin Vb.Rab11a.Rab11-FIP2 triple complex inhibited the export of NPC1L1. Expression of the dominant-negative mutants of myosin Vb, Rab11a, or Rab11-FIP2 decreased the cellular cholesterol uptake by blocking the transport of NPC1L1 to the PM. These results suggest that the efficient transport of NPC1L1 to the PM is dependent on the microfilament-associated myosin Vb.Rab11a.Rab11-FIP2 triple complex.