Prolonged insulin stimulation down-regulates GLUT4 through oxidative stress-mediated retromer inhibition by a protein kinase CK2-dependent mechanism in 3T3-L1 adipocytes.
Although insulin acutely stimulates glucose uptake by promotion of GLUT4 translocation from intracellular compartments to the plasma membrane in adipocytes and muscles, long term insulin stimulation causes GLUT4 depletion that is particularly prominent in the insulin-responsive GLUT4 storage compartment. This effect is caused mainly by accelerated lysosomal degradation of GLUT4, although the mechanism is not fully defined. Here we show that insulin acutely induced dissociation of retromer components from the low density microsomal membranes of 3T3-L1 adipocytes that was accompanied by disruption of the interaction of Vps35 with sortilin. This insulin effect was dependent on the activity of protein kinase CK2 but not phosphatidylinositol 3-kinase or extracellular signal-regulated kinase 1/2. Knockdown of Vps26 decreased GLUT4 to a level comparable with that with insulin stimulation for 4 h. Vps35 with a mutation in the CK2 phosphorylation motif (Vps35-S7A) was resistant to insulin-induced dissociation from the low density microsomal membrane, and its overexpression attenuated GLUT4 down-regulation with insulin. Furthermore, insulin-generated hydrogen peroxide was an upstream mediator of the insulin action on retromer and GLUT4. These results suggested that insulin-generated oxidative stress switches the GLUT4 sorting direction to lysosomes through inhibition of the retromer function in a CK2-dependent manner.
From the Department of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan.
Jinhui
J
Ma
Yuko
Y
Nakagawa
Itaru
I
Kojima
Hiroshi
H
Shibata
D016475:3T3 Cells; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D047390:Casein Kinase II / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D055785:Gene Knockdown Techniques; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000378:metabolism / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D008081:Liposomes / Q000378:metabolism; D051379:Mice; D008861:Microsomes / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D059748:Proteolysis / Q000187:drug effects; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism; D000099183:Sortilin
D033942:Adaptor Proteins, Vesicular Transport; D047390:Casein Kinase II; D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D007328:Insulin; D008081:Liposomes; D048052:Mitogen-Activated Protein Kinase 3; D019869:Phosphatidylinositol 3-Kinases; D033921:Vesicular Transport Proteins; D000099183:Sortilin; C495693:Slc2a4 protein, mouse; C089989:Vps26 protein, mouse; C101274:Vps35 protein, mouse
Adipocyte; Glut4; Insulin; Membrane Trafficking; Retromer; Signal Transduction