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Hexosamine Biosynthesis Pathway Flux Contributes To Insulin Resistance Via Altering Membrane Phosphatidylinositol 4,5-Bisphosphate And Cortical Filamentous Actin, P. Bhonagiri, G. R. Pattar, E. M. Horvath, K. M. Habegger, Ann Mccarthy, J. S. Elmendorf

Ann Marie McCarthy

We recently found that plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP(2))-regulated filamentous actin (F-actin) polymerization was diminished in hyperinsulinemic cell culture models of insulin resistance. Here we delineated whether increased glucose flux through the hexosamine biosynthesis pathway (HBP) causes the PIP(2)/F-actin dysregulation and insulin resistance induced by hyperinsulinemia. Increased HBP activity was detected in 3T3-L1 adipocytes cultured under conditions closely resembling physiological hyperinsulinemia (5 nm insulin for 12 h) and in cells where HBP activity was amplified by 2 mm glucosamine (GlcN). Both the physiological hyperinsulinemia and experimental GlcN challenge induced comparable losses of PIP(2) and F-actin. In addition to protecting against …