Endocytosis of the Aspartic Acid/Glutamic Acid Transporter Dip5 Is Triggered by Substrate-Dependent Recruitment of the Rsp5 Ubiquitin Ligase via the Arrestin-Like Protein Aly2
Endocytosis of the Aspartic Acid/Glutamic Acid Transporter Dip5 Is Triggered by Substrate-Dependent Recruitment of the Rsp5 Ubiquitin Ligase via the Arrestin-Like Protein Aly2
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DOI：
10.1128/mcb.00464-10
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发表时间：
2010-12-01
影响因子：
5.3
通讯作者：
Maeda, Tatsuya
中科院分区：
文献类型：
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作者：
Hatakeyama, Riko;Kamiya, Masao;Maeda, Tatsuya
营养转运蛋白的内吞作用在各种条件下受到刺激，例如营养物质的可利用性提高。在酿酒酵母中，内吞作用由E3泛素连接酶Rsp 5催化的转运蛋白的泛素化触发。然而，在某些条件下，泛素化是如何加速的仍然不清楚。在这里，我们表明，密切相关的蛋白质Aly 2/Art 3和Aly 1/Art 6，这是很差的特点的arrestin样蛋白家族的成员，介导的天冬氨酸/谷氨酸转运蛋白Dip 5的内吞作用。在aly 2 δ细胞中，Dip 5稳定在质膜上，不能有效地内吞。Dip 5的有效泛素化依赖于Aly 2。aly 1 δ细胞也显示Dip 5内吞作用的缺陷，尽管不如aly 2 δ细胞显著。Aly 2在体内与Rsp 5的PY基序以及Dip 5物理相互作用，从而作为连接Rsp 5与Dip 5以实现Dip 5泛素化的接头。重要的是，Aly 2和Dip 5之间的相互作用响应于升高的天冬氨酸可用性而加速。该结果表明，Dip 5内吞作用的调节是通过Aly 2动态募集Rsp 5来实现的。
Endocytosis of nutrient transporters is stimulated under various conditions, such as elevated nutrient availability. In Saccharomyces cerevisiae, endocytosis is triggered by ubiquitination of transporters catalyzed by the E3 ubiquitin ligase Rsp5. However, how the ubiquitination is accelerated under certain conditions remains obscure. Here we demonstrate that closely related proteins Aly2/Art3 and Aly1/Art6, which are poorly characterized members of the arrestin-like protein family, mediate endocytosis of the aspartic acid/glutamic acid transporter Dip5. In aly2 Delta cells, Dip5 is stabilized at the plasma membrane and is not endocytosed efficiently. Efficient ubiquitination of Dip5 is dependent on Aly2. aly1 Delta cells also show deficiency in Dip5 endocytosis, although less remarkably than aly2 Delta cells. Aly2 physically interacts in vivo with Rsp5 at its PY motif and also with Dip5, thus serving as an adaptor linking Rsp5 with Dip5 to achieve Dip5 ubiquitination. Importantly, the interaction between Aly2 and Dip5 is accelerated in response to elevated aspartic acid availability. This result indicates that the regulation of Dip5 endocytosis is accomplished by dynamic recruitment of Rsp5 via Aly2.