2-Deoxyglucose Impairs Saccharomyces cerevisiae Growth by Stimulating Snf1-Regulated and α-Arrestin-Mediated Trafficking of Hexose Transporters 1 and 3

Abstract

The glucose analog 2-deoxyglucose (2DG) inhibits the growth of Saccharomyces cerevisiae and human tumor cells, but its modes of action have not been fully elucidated. Yeast cells lacking Snf1 (AMP-activated protein kinase) are hypersensitive to 2DG. Overexpression of either of two low-affinity, high-capacity glucose transporters, Hxt1 and Hxt3, suppresses the 2DG hypersensitivity of snf1Δ cells. The addition of 2DG or the loss of Snf1 reduces HXT1 and HXT3 expression levels and stimulates transporter endocytosis and degradation in the vacuole. 2DG-stimulated trafficking of Hxt1 and Hxt3 requires Rod1/Art4 and Rog3/Art7, two members of the α-arrestin trafficking adaptor family. Mutations in ROD1 and ROG3 that block binding to the ubiquitin ligase Rsp5 eliminate Rod1- and Rog3-mediated trafficking of Hxt1 and Hxt3. Genetic analysis suggests that Snf1 negatively regulates both Rod1 and Rog3, but via different mechanisms. Snf1 activated by 2DG phosphorylates Rod1 but fails to phosphorylate other known targets, such as the transcriptional repressor Mig1. We propose a novel mechanism for 2DG-induced toxicity whereby 2DG stimulates the modification of α-arrestins, which promote glucose transporter internalization and degradation, causing glucose starvation even when cells are in a glucose-rich environment.

ACKNOWLEDGMENTS

This work was supported by NIH R01 research grant GM46443 (to M.C.S.) and by NIH R01 research grant GM21841 and funds from the UC Berkeley Energy Biosciences Institute (to J.T.). A.F.O was supported by development funds from the Department of Cell Biology (University of Pittsburgh), as well as by NIH R01 research grants GM21841 (to J.T.), DA014204-11 (to A. Sorkin, University of Pittsburgh), and GM75061 (to J. L. Brodsky, University of Pittsburgh).

We gratefully acknowledge helpful discussions with members of the Brodsky laboratory, and we thank Adam Kwiatkowski (University of Pittsburgh) for the use of his confocal microscope, Hugh Pelham (LMB, MRC, Cambridge, United Kingdom) for the 9arrΔ strain, Widmar Tanner (Universität Regensburg, Regensburg, Germany) for the Hxt1-GFP-expressing plasmid pVTU100, Chris Burd (Yale University) for the rsp5-1 strain, George van der Merwe (University of Guelph, Guelph, Ontario, Canada) for the Hxt3-GFP rsp5-1 strain, and Chris Alvaro (UC Berkeley) for plasmids expressing Rod1-3HA and Rog3-3HA.