GLUT4 (also known as SLC2A4) is essential for glucose uptake in skeletal muscles and adipocytes, which play central roles in whole-body glucose metabolism. Here, using direct stochastic optical reconstruction microscopy (dSTORM) to investigate the characteristics of plasma-membrane-fused GLUT4 at the single-molecule level, we have demonstrated that insulin and insulin resistance regulate the spatial organization of GLUT4 in adipocytes. Stimulation with insulin shifted the balance of GLUT4 on the plasma membrane toward a more dispersed configuration. In contrast, insulin resistance induced a more clustered distribution of GLUT4 and increased the mean number of molecules per cluster. Furthermore, our data demonstrate that the F(5)QQI motif and lipid rafts mediate the maintenance of GLUT4 clusters on the plasmamembrane. Mutation of F(5)QQI (F(5)QQA-GLUT4) induced a more clustered distribution of GLUT4; moreover, destruction of lipid rafts in adipocytes expressing F(5)QQA-GLUT4 dramatically decreased the percentage of large clusters and the mean number of molecules per cluster. In conclusion, our data clarify the effects of insulin stimulation or insulin resistance on GLUT4 reorganization on the plasma membrane and reveal new pathogenic mechanisms of insulin resistance.
1.Chinese Acad Sci, Kunming Inst Bot, State Key Lab Phytochem & Plant Resources West Ch, Kunming 650201, Yunnan, Peoples R China 2.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Electroanal Chem, Changchun 130022, Jilil, Peoples R China
Gao, Lan,Chen, Junling,Gao, Jing,et al. Super-resolution microscopy reveals the insulin-resistance-regulated reorganization of GLUT4 on plasma membranes[J]. JOURNAL OF CELL SCIENCE,2017,130(2):396-405.