title: A dominant-negative p38 MAPK mutant and novel selective inhibitors of p38 MAPK reduce insulin-stimulated glucose uptake in 3T3-L1 adipocytes without affecting GLUT4 translocation.
abstract: Participation of p38 mitogen-activated protein kinase (p38) in insulin-induced glucose uptake was suggested using pyridinylimidazole p38 inhibitors (e.g. SB203580). However, the role of p38 in insulin action remains controversial. We further test p38 participation in glucose uptake using a dominant-negative p38 mutant and two novel pharmacological p38 inhibitors related to but different from SB203580. We present the structures and activities of the azaazulene pharmacophores A291077 and A304000. p38 kinase activity was inhibited in vitro by A291077 and A304000 (IC(50) = 0.6 and 4.7 microm). At higher concentrations A291077 but not A304000 inhibited JNK2alpha (IC(50) = 3.5 microm). Pretreatment of 3T3-L1 adipocytes and L6 myotubes expressing GLUT4myc (L6-GLUT4myc myotubes) with A291077, A304000, SB202190, or SB203580 reduced insulin-stimulated glucose uptake by 50-60%, whereas chemical analogues inert toward p38 were ineffective. Expression of an inducible, dominant-negative p38 mutant in 3T3-L1 adipocytes reduced insulin-stimulated glucose uptake. GLUT4 translocation to the cell surface, immunodetected on plasma membrane lawns of 3T3-L1 adipocytes or on intact L6-GLUT4myc myotubes, was not altered by chemical or molecular inhibition of p38. We propose that p38 contributes to enhancing GLUT4 activity, thereby increasing glucose uptake. In addition, the azaazulene class of inhibitors described will be useful to decipher cellular actions of p38 and JNK.
authors.affiliation: Programme in Cell Biology, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
authors.forename: Romel
authors.initials: R
authors.lastname: Somwar
authors.forename: Sandra
authors.initials: S
authors.lastname: Koterski
authors.forename: Gary
authors.initials: G
authors.lastname: Sweeney
authors.forename: Richard
authors.initials: R
authors.lastname: Sciotti
authors.forename: Stevan
authors.initials: S
authors.lastname: Djuric
authors.forename: Cathy
authors.initials: C
authors.lastname: Berg
authors.forename: James
authors.initials: J
authors.lastname: Trevillyan
authors.forename: Philipp E
authors.initials: PE
authors.lastname: Scherer
authors.forename: Christina M
authors.initials: CM
authors.lastname: Rondinone
authors.forename: Amira
authors.initials: A
authors.lastname: Klip
mesh_terms: D016475:3T3 Cells; D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015723:Gene Library; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D007739:L Cells; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000378:metabolism; D016133:Polymerase Chain Reaction; D021381:Protein Transport; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: C557211:A 304000; D004791:Enzyme Inhibitors; D051275:Glucose Transporter Type 4; D007093:Imidazoles; D007211:Indoles; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D011725:Pyridines; C495692:SLC2A4 protein, human; C495693:Slc2a4 protein, mouse; C495694:Slc2a4 protein, rat; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose; C093642:SB 203580