PKB inhibition prevents the stimulatory effect of insulin on glucose transport and protein translocation but not the antilipolytic effect in rat adipocytes.
We identified 1-(5 chloronaphthalenesulfonyl)-1H-hexahydro-1, 4-diazepine, also known as ML-9, as a powerful inhibitor of PKB activity in different cells as well as of recombinant PKB. It also inhibits other downstream serine/threonine kinases, such as PKA and p90 S6 kinase, but not upstream tyrosine phosphorylation or PI3-kinase activation in response to insulin. We compared the effects of ML-9 and wortmannin on several insulin-stimulated effects in isolated rat fat cells. Both ML-9 and wortmannin inhibited glucose transport and GLUT4/IGF II receptor translocation to the plasma membrane. In contrast, only wortmannin inhibited the antilipolytic effect and PDE3B activation by insulin. Thus, ML-9 inhibits PKB but not PI3-kinase activation in response to insulin and is useful to differentiate between these effects. Both PI3-kinase and PKB are important for glucose transport and intracellular protein translocation while PKB does not appear to play an important role for the antilipolytic effect or activation of PDE3B in response to insulin.
Smith
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U
The Lundberg Laboratory for Diabetes Research, Department of Internal Medicine, Goteborg University, Sahlgrenska University Hospital, Goteborg, S-413 45, Sweden. ulf.smith@medic.gu.se
Carvalho
E
E
Mosialou
E
E
Beguinot
F
F
Formisano
P
P
Rondinone
C
C
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects*; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001381:Azepines / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4; D007328:Insulin / Q000494:pharmacology*; D007329:Insulin Antagonists / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008066:Lipolysis / Q000187:drug effects; D008297:Male; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009124:Muscle Proteins; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar; D014443:Tyrosine / Q000378:metabolism; D000077191:Wortmannin
D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000730:Androstadienes; D001381:Azepines; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D004791:Enzyme Inhibitors; D005947:Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D007329:Insulin Antagonists; D007335:Insulin-Like Growth Factor II; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D014443:Tyrosine; D000077191:Wortmannin; C495694:Slc2a4 protein, rat; C056218:ML 9; C517294:Pde3b protein, rat