Abstract
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 aly2Δ cells, Dip5 is stabilized at the plasma membrane and is not endocytosed efficiently. Efficient ubiquitination of Dip5 is dependent on Aly2. aly1Δ cells also show deficiency in Dip5 endocytosis, although less remarkably than aly2Δ 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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Transport Systems / genetics
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Amino Acid Transport Systems / metabolism*
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Amino Acid Transport Systems, Basic / genetics
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Amino Acid Transport Systems, Basic / metabolism
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Arrestin / genetics
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Arrestin / metabolism*
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Arrestins / genetics
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Arrestins / metabolism*
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Aspartic Acid / metabolism
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Endocytosis / physiology*
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Endosomal Sorting Complexes Required for Transport / genetics
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Endosomal Sorting Complexes Required for Transport / metabolism*
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Ubiquitin-Protein Ligase Complexes / genetics
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Ubiquitin-Protein Ligase Complexes / metabolism*
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Ubiquitination
Substances
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Aly1 protein, S cerevisiae
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Aly2 protein, S cerevisiae
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Amino Acid Transport Systems
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Amino Acid Transport Systems, Basic
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Arrestin
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Arrestins
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CAN1 protein, S cerevisiae
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DIP5 protein, S cerevisiae
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Endosomal Sorting Complexes Required for Transport
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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Aspartic Acid
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Ubiquitin-Protein Ligase Complexes
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RSP5 protein, S cerevisiae