An insulin-stimulated proteolytic mechanism links energy expenditure with glucose uptake

Mechanisms to coordinately regulate oxidative metabolism and glucose transport into cells are not well described. In muscle and fat, insulin mobilizes GLUT4 glucose transporters to the cell surface in part by stimulating the site-specific endoproteolytic cleavage of TUG proteins. Here, we show that the TUG C-terminal cleavage product enters the nucleus, binds the transcriptional 30 regulators PGC-1a and PPARg, and increases oxidative metabolism, thermogenic protein expression, and energy expenditure. The PPARg2 Pro12Gly polymorphism, which confers reduced diabetes risk, enhances TUG binding. The TUG cleavage product stabilizes PGC-1a, so that both proteins are susceptible to an Ate1 arginyltransferase -dependent degradation mechanism. We conclude that TUG cleavage coordinates energy expenditure with glucose 35 uptake, and that alterations in this pathway may contribute to metabolic disease. Overall design: Examination of gene expression differences between wiltype mice and transgenic mice with constitutive, insulin-independent TUG cleavage in muscle