Sex and Insulin Resistance Define a Cell Autonomous Supernetwork of Protein Phosphorylation

Insulin resistance is an important factor in the pathophysiology of many metabolic disorders. The aim of this study was to uncover the cell autonomous determinants of insulin resistance using induced pluripotent stem cell (iPSC)-derived myoblasts (iMyos). Here, we found that iMyos from insulin resistant non-diabetic individuals show impaired insulin signaling, defective insulin-stimulated glucose uptake and glycogen synthase activity compared to insulin sensitive individuals. Global phosphoproteomic analysis uncovered a large network of altered protein phosphorylations in insulin resistance, mostly outside the canonical insulin-signaling cascade. More surprisingly, we observed striking differences in the phosphoproteomic signature from male versus female subjects, including changes in DNA and RNA processing, GTPase signaling, and SUMOylation/ubiquitination. These findings unravel cell autonomous mechanisms underlying insulin resistance and demonstrate a previously unrecognized supernetwork of cell signaling differences in males and females that must be considered in understanding the molecular basis of sex-based differences in normal physiology and disease.