TBC1D1 and Insulin resistance: Disruption of GLUT4 trafficking is associated with impaired glucose uptake and ensuing insulin resistance (Mueckler, 2001), and the phosphorylation change on TBC1D1 and GLUT4 along with the predicted increase in AKT activity suggest that IF improves insulin sensitivity in the heart by modulating glucose uptake and resetting aberrations in insulin signaling via increasing phosphorylation of such proteins.