Rab proteins mediate Golgi transport of caveola-internalized glycosphingolipids and correct lipid trafficking in Niemann-Pick C cells
Rab proteins mediate Golgi transport of caveola-internalized glycosphingolipids and correct lipid trafficking in Niemann-Pick C cells
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DOI：
10.1172/jci200215420
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发表时间：
2002-06-01
影响因子：
15.9
通讯作者：
Pagano, RE
中科院分区：
文献类型：
--
作者：
Choudhury, A;Dominguez, M;Pagano, RE
我们最近表明，人类皮肤成纤维细胞几乎完全通过涉及小窝的网格蛋白独立机制内化糖鞘脂乳糖神经酰胺和球糖苷的荧光类似物。相比之下，鞘磷脂类似物通过网格蛋白依赖性途径和小凹途径大致相同地内化。在这里，我们进一步表征了鞘糖脂的小凹途径，表明高尔基体靶向通过小凹内化的鞘脂需要微管和磷酸肌醇3-激酶，并且在表达显性失活 Rab7 和 Rab9 构建体的细胞中受到抑制。此外，在 Niemann-Pick C 型 (NP-C) 脂质贮积病成纤维细胞中过度表达野生型 Rab7 或 Rab9（但不是 Rab11）可纠正脂质运输缺陷，包括恢复高尔基体对荧光乳糖神经酰胺和内源 GM(1) 神经节苷脂的靶向，以及细胞内胆固醇储备的显着减少。我们的结果证明了 Rab7 和 Rab9 在高尔基体靶向糖鞘脂中的作用，并提出了一种恢复 NP-C 细胞正常脂质运输的新治疗方法。
We recently showed that human skin fibroblasts internalize fluorescent analogues of the glycosphingolipids lactosylceramide and globoside almost exclusively by a clathrin-independent mechanism involving caveolae. In contrast, a sphingomyelin analogue is internalized approximately equally via clathrin-dependent and caveolar routes. Here, we further characterized the caveolar pathway for glycosphingolipids, showing that Golgi targeting of sphingolipids internalized via caveolae required microtubules and phosphoinositol 3-kinases and was inhibited in cells expressing dominant-negative Rab7 and Rab9 constructs. In addition, overexpression of wild-type Rab7 or Rab9 (but not Rab11) in Niemann-Pick type C (NP-C) lipid storage disease fibroblasts resulted in correction of lipid trafficking defects, including restoration of Golgi targeting of fluorescent lactosylceramide and endogenous GM(1) ganglioside, and a dramatic reduction in intracellular cholesterol stores. Our results demonstrate a role for Rab7 and Rab9 in the Golgi targeting of glycosphingolipids and suggest a new therapeutic approach for restoring normal lipid trafficking in NP-C cells.