G protein-coupled receptor endocytosis in ADP-ribosylation factor 6-depleted cells
G protein-coupled receptor endocytosis in ADP-ribosylation factor 6-depleted cells
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DOI：
10.1074/jbc.m411456200
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发表时间：
2005-02-18
影响因子：
4.8
通讯作者：
Claing, A
中科院分区：
文献类型：
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作者：
Houndolo, T;Boulay, PL;Claing, A
G蛋白偶联受体的内化是由几个重要的蛋白质调控的，这些蛋白质协同作用，精细地控制这一复杂的细胞过程。在这里，我们应用RNA干扰方法来证明adp -核糖基化因子6 （ARF6）对多种受体的内吞作用至关重要。HEK 293细胞中内源性ARF6表达的减少导致β(2)-肾上腺素能受体内化的相关抑制，此前的研究认为β(2)-肾上腺素能受体内化是通过网格蛋白包被囊泡途径被隔离的。此外，当细胞中内源性ARF6水平降低时，其他通过这种内吞途径内化的受体，即血管紧张素1型受体和血管加压素2型受体，其隔离能力也受到损害。有趣的是，内皮素B型受体的内吞作用在arf6缺失的细胞中也被显著抑制，其特征是通过小泡途径内化。相反，血管活性肠肽受体的内化不受ARF6水平降低的影响。最后，在arf6缺失的细胞中，乙酰胆碱-毒蕈碱2型受体通过非网格蛋白包被囊泡途径的内化也被抑制。综上所述，我们的研究结果表明，无论采用何种内吞途径，ARF6蛋白在大多数G蛋白偶联受体的内化过程中都起着至关重要的作用。然而，这种现象并不普遍。在某些情况下，另一种ARF异构体或其他蛋白质可能是调节内吞过程所必需的。
The internalization of G protein-coupled receptors is regulated by several important proteins that act in concert to finely control this complex cellular process. Here, we have applied the RNA interference approach to demonstrate that ADP-ribosylation factor 6 (ARF6) is essential for the endocytosis of a broad variety of receptors. Reduction of endogenous expression of ARF6 in HEK 293 cells resulted in a correlated inhibition of the beta(2)-adrenergic receptor internalization previously characterized as being sequestered via the clathrin-coated vesicle pathway. Furthermore, other receptors internalizing via this endocytic route, namely the angiotensin type 1 receptor and the vasopressin type 2 receptor, were also impaired in their ability to be sequestered when levels of endogenous ARF6 in cells were reduced. Interestingly, endocytosis of the endothelin type B receptor, characterized as being internalized via the caveolae pathway, was also markedly inhibited in ARF6-depleted cells. In contrast, internalization of the vasoactive intestinal peptide receptor was unaffected by reduced levels of ARF6. Finally, internalization of the acetylcholine-muscarinic type 2 receptor via the non-clathrin-coated vesicle pathway was also inhibited in ARF6-depleted cells. Taken together, our results demonstrate that ARF6 proteins play an essential role in the internalization process of most G protein-coupled receptors regardless of the endocytic route being utilized. However, this phenomenon is not general. In some cases, another ARF isoform or other proteins may be essential to regulate the endocytic process.