Lysosomal trafficking of the glucose transporter GLUT1 requires sequential regulation by TXNIP and ubiquitin

• Published in: iScience 2023-03, Vol.26 (3), p.106150-106150, Article 106150
• Main Authors: Qualls-Histed, Susan J., Nielsen, Casey P., MacGurn, Jason A.
• Format: Article
• Language: English
• Subjects: Biological sciences; Cell biology; Molecular biology
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2023.106150

Glucose transporters are gatekeepers of cellular glucose metabolism. Understanding how their activity is regulated can provide insight into mechanisms of glucose homeostasis and diseases arising from dysregulation of glucose transport. Glucose stimulates endocytosis of the human glucose transporter GLUT1, but several important questions remain surrounding the intracellular trafficking itinerary of GLUT1. Here, we report that increased glucose availability triggers lysosomal trafficking of GLUT1 in HeLa cells, with a subpopulation of GLUT1 routed through ESCRT-associated late endosomes. This itinerary requires the arrestin-like protein TXNIP, which interacts with both clathrin and E3 ubiquitin ligases to promote GLUT1 lysosomal trafficking. We also find that glucose stimulates GLUT1 ubiquitylation, which promotes its lysosomal trafficking. Our results suggest that excess glucose first triggers TXNIP-mediated endocytosis of GLUT1 and, subsequently, ubiquitylation to promote lysosomal trafficking. Our findings underscore how complex coordination of multiple regulators is required for fine-tuning of GLUT1 stability at the cell surface. [Display omitted] •Substrate transport triggers GLUT1 endocytosis and trafficking to lysosomes•TXNIP regulates GLUT1 trafficking via interactions with clathrin and ubiquitin ligases•Ubiquitination of GLUT1 is regulated by glucose levels•GLUT1 cytosol-facing lysines are required for glucose-stimulated lysosomal trafficking Biological sciences; Molecular biology; Cell biology