Activation of the Small G Protein Arf6 by Dynamin2 through Guanine Nucleotide Exchange Factors in Endocytosis.
Activation of the Small G Protein Arf6 by Dynamin2 through Guanine Nucleotide Exchange Factors in Endocytosis.
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DOI：
10.1038/srep14919
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发表时间：
2015-10-27
影响因子：
4.6
通讯作者：
Kanaho Y
中科院分区：
文献类型：
--
作者：
Okada R;Yamauchi Y;Hongu T;Funakoshi Y;Ohbayashi N;Hasegawa H;Kanaho Y
小G蛋白Arf 6和GT3发动蛋白2（Dyn2）在网格蛋白介导的内吞作用（CME）中起关键作用。然而，它们的功能关系仍然模糊不清。在这里，我们表明，Arf 6的功能作为下游分子的Dyn2在CME。在HeLa细胞中过表达的野生型Dyn2显著激活Arf 6，而缺乏GTP酶的Dyn2突变体则不能。在Arf6特异性鸟嘌呤核苷酸交换因子中，EFA6A、EFA6B和EFA6D特异性地与Dyn2相互作用。此外，显性失活突变体的过表达或EFA6B和EFA6D的敲低显著抑制Dyn2诱导的Arf6活化。最后，过表达针对Dyn2的EFA6B的结合区肽或敲低EFA6B和EFA6D显著抑制网格蛋白介导的转铁蛋白摄取。这些结果为Dyn2通过EFA6B和EFA6D在CME中以依赖于Dyn2的GTdR活性的方式激活Arf 6的新机制提供了证据。
The small G protein Arf6 and the GTPase dynamin2 (Dyn2) play key roles in clathrin-mediated endocytosis (CME). However, their functional relationship remains obscure. Here, we show that Arf6 functions as a downstream molecule of Dyn2 in CME. Wild type of Dyn2 overexpressed in HeLa cells markedly activates Arf6, while a GTPase-lacking Dyn2 mutant does not. Of the Arf6-specific guanine nucleotide exchange factors, EFA6A, EFA6B, and EFA6D specifically interact with Dyn2. Furthermore, overexpression of dominant negative mutants or knockdown of EFA6B and EFA6D significantly inhibit Dyn2-induced Arf6 activation. Finally, overexpression of the binding region peptide of EFA6B for Dyn2 or knockdown of EFA6B and EFA6D significantly suppresses clathrin-mediated transferrin uptake. These results provide evidence for a novel Arf6 activation mechanism by Dyn2 through EFA6B and EFA6D in CME in a manner dependent upon the GTPase activity of Dyn2.