Rockefeller University Press, Journal of Cell Biology, 2(196), p. 247-259, 2012
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Endocytosis regulates the plasma membrane protein landscape in response to environmental cues. In yeast, the endocytosis of transporters depends on their ubiquitylation by the Nedd4-like ubiquitin ligase Rsp5, but how extracellular signals trigger this ubiquitylation is unknown. Various carbon source transporters are known to be ubiquitylated and endocytosed when glucose-starved cells are exposed to glucose. We show that this required the conserved arrestin-related protein Rod1/Art4, which was activated in response to glucose addition. Indeed, Rod1 was a direct target of the glucose signaling pathway composed of the AMPK homologue Snf1 and the PP1 phosphatase Glc7/Reg1. Glucose promoted Rod1 dephosphorylation and its subsequent release from a phospho-dependent interaction with 14-3-3 proteins. Consequently, this allowed Rod1 ubiquitylation by Rsp5, which was a prerequisite for transporter endocytosis. This paper therefore demonstrates that the arrestin-related protein Rod1 relays glucose signaling to transporter endocytosis and provides the first molecular insights into the nutrient-induced activation of an arrestin-related protein through a switch in post-translational modifications.