Potentiation of insulin-stimulated glucose transport by the AMP-activated protein kinase.
Data from the use of activators and inhibitors of the AMP-activated protein kinase (AMPK) suggest that AMPK increases sensitivity of glucose transport to stimulation by insulin in muscle cells. We assayed insulin action after adenoviral (Ad) transduction of constitutively active (CA; a truncated form of AMPKalpha(1)) and dominant-negative (DN; which depletes endogenous AMPKalpha) forms of AMPKalpha (Ad-AMPKalpha-CA and Ad-AMPKalpha-DN, respectively) into C(2)C(12) myotubes. Compared with control (Ad-green fluorescent protein), Ad-AMPK-CA increased the ability of insulin to stimulate glucose transport. The increased insulin action in cells expressing AMPK-CA was suppressed by compound C (an AMPK inhibitor). Exposure of cells to 5-aminoimidazole-4-carboxamide-1beta-D-ribofuranoside (an AMPK activator) increased insulin action in uninfected myotubes and myotubes transduced with green fluorescent protein but not in Ad-AMPK-DN-infected myotubes. In Ad-AMPK-CA-transduced cells, serine phosphorylation of insulin receptor substrate 1 was decreased at a mammalian target of rapamycin (or p70 S6 kinase) target site that has been reported to be associated with insulin resistance. These data suggest that, in myotubes, activated AMPKalpha(1) is sufficient to increase insulin action and that the presence of functional AMPKalpha is required for 5-aminoimidazole-4-carboxamide-1beta,D-ribofuranoside-related increases in insulin action.
Ju
Jeong-Sun
JS
Department of Biology, Saint Louis University, 3507 Laclede Avenue, St. Louis, MO 63103, USA.
Gitcho
Michael A
MA
Casmaer
Carter A
CA
Patil
Pankaj B
PB
Han
Dae-Gyue
DG
Spencer
Susan A
SA
Fisher
Jonathan S
JS
D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D004357:Drug Synergism; D020536:Enzyme Activators / Q000494:pharmacology; D005799:Genes, Dominant; D005947:Glucose / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D007004:Hypoglycemic Agents / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins; D007527:Isoenzymes / Q000494:pharmacology; D049408:Luminescent Agents; D051379:Mice; D009097:Multienzyme Complexes / Q000235:genetics / Q000494:pharmacology*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000494:pharmacology*; D012265:Ribonucleotides / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D058570:TOR Serine-Threonine Kinases
D020536:Enzyme Activators; D007004:Hypoglycemic Agents; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D007527:Isoenzymes; D049408:Luminescent Agents; D009097:Multienzyme Complexes; D010750:Phosphoproteins; D012265:Ribonucleotides; D049452:Green Fluorescent Proteins; D000620:Aminoimidazole Carboxamide; D011494:Protein Kinases; C546843:mTOR protein, mouse; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide; D005947:Glucose