TBC1D4 and Insulin resistance: In addition to DAGs, the accumulation of ceramides in skeletal muscle may also contribute to insulin resistance by attenuating phosphorylation of protein kinase B (PKB/Akt) (Schmitz-Peiffer et al., 1999; Bruce et al., 2012), a step required for insulin-mediated phosphorylation of Rab-GAP activating proteins (AS160/TBC1D4) and the induction of glucose transporter (GLUT4) translocation to the plasma membrane.