AMP-activated protein kinase activation increases phosphorylation of glycogen synthase kinase 3beta and thereby reduces cAMP-responsive element transcriptional activity and phosphoenolpyruvate carboxykinase C gene expression in the liver.
AMP-activated protein kinase (AMPK) activation reportedly suppresses transcriptional activity of the cAMP-responsive element (CRE) in the phosphoenolpyruvate carboxykinase C (PEPCK-C) promoter and reduces hepatic PEPCK-C expression. Although a previous study found TORC2 phosphorylation to be involved in the suppression of AMPK-mediated CRE transcriptional activity, we herein present evidence that glycogen synthase kinase 3beta (GSK3beta) phosphorylation induced by AMPK also plays an important role. We initially found that injecting fasted mice with 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) markedly increased Ser-9 phosphorylation of hepatic GSK3beta within 15 min. Stimulation with AICAR or the GSK3beta inhibitor SB-415286 strongly inhibited CRE-containing promoter activity in HepG2 cells. Using the Gal4-based transactivation assay system, the transcriptional activity of cAMP-response element-binding protein (CREB) was suppressed by both AICAR and SB415286, whereas that of TORC2 was repressed significantly by AICAR but very slightly by SB415286. These results show inactivation of GSK3beta to directly inhibit CREB but not TORC2. Importantly, the AICAR-induced suppression of PEPCK-C expression was shown to be blunted by overexpression of GSK3beta(S9G) but not wild-type GSK3beta. In addition, AICAR stimulation decreased, whereas Compound C (AMPK inhibitor) increased CREB phosphorylation (Ser-129) in HepG2 cells. The time-courses of decreased CREB phosphorylation (Ser-129) and increased GSK3beta phosphorylation were very similar. Furthermore, AMPK-mediated GSK3beta phosphorylation was inhibited by an Akt-specific inhibitor in HepG2 cells, suggesting involvement of the Akt pathway. In summary, phosphorylation (Ser-9) of GSK3beta is very likely to be critical for AMPK-mediated PEPCK-C gene suppression. Reduced CREB phosphorylation (Ser-129) associated with inactivation of GSK3beta by Ser-9 phosphorylation may be the major mechanism underlying PEPCK-C gene suppression by AMPK-activating agents such as biguanide.
Horike
Nanao
N
Department of Physiological Chemistry and Metabolism, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan 734-8553.
Sakoda
Hideyuki
H
Kushiyama
Akifumi
A
Ono
Hiraku
H
Fujishiro
Midori
M
Kamata
Hideaki
H
Nishiyama
Koichi
K
Uchijima
Yasunobu
Y
Kurihara
Yukiko
Y
Kurihara
Hiroki
H
Asano
Tomoichiro
T
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D001645:Biguanides / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D005943:Gluconeogenesis; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D051379:Mice; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism*; D010766:Phosphorylation; D012265:Ribonucleotides / Q000378:metabolism; D014158:Transcription, Genetic
D001645:Biguanides; D017362:Cyclic AMP Response Element-Binding Protein; D047908:Intracellular Signaling Peptides and Proteins; D012265:Ribonucleotides; D000620:Aminoimidazole Carboxamide; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3; D055372:AMP-Activated Protein Kinases; C521898:PCK1 protein, human; D010729:Phosphoenolpyruvate Carboxykinase (GTP); C031143:AICA ribonucleotide
Diabetes. 2001 May;50(5):937-46
11334436
Circ Res. 2007 Feb 16;100(3):328-41
17307971
Diabetes. 2002 Oct;51(10):2903-10
12351425
J Biol Chem. 1998 Nov 27;273(48):31629-32
9822619
Nature. 2005 Oct 20;437(7062):1109-11
16148943
Front Biosci. 2007 Jan 01;12:1814-32
17127423
J Biol Chem. 2003 Jul 11;278(28):25802-7
12734207
Diabetes. 2003 Jul;52(7):1649-54
12829628
Science. 2005 Feb 18;307(5712):1098-101
15718470
J Biol Chem. 2001 Apr 27;276(17):13505-8
11279224
Nutr Metab (Lond). 2005 Nov 21;2:33
16300682
J Pharmacol Exp Ther. 2006 Jan;316(1):17-24
16169938
J Biol Chem. 1999 Mar 26;274(13):8813-22
10085123
Cell. 2004 Oct 1;119(1):61-74
15454081
J Appl Physiol (1985). 1997 Jan;82(1):219-25
9029219
J Clin Invest. 2001 Oct;108(8):1167-74
11602624
Diabetes. 2006 Apr;55(4):988-95
16567520
J Biol Chem. 1986 Jul 25;261(21):9721-6
3015903
Int J Biochem Cell Biol. 1998 Jan;30(1):27-38
9597751
Diabetes. 2000 Jun;49(6):896-903
10866040
Biochem J. 2005 Dec 15;392(Pt 3):633-9
16176184
Diabetologia. 1996 Oct;39(10):1148-55
8897001
J Biol Chem. 1994 Dec 23;269(51):32187-93
7798217
Endocrinology. 2002 Feb;143(2):674-82
11796524
Biochem Pharmacol. 2006 May 28;71(11):1637-47
16620785
Nature. 1993 Oct 28;365(6449):855-9
8413673
Mol Cell Biol. 2006 Jan;26(1):63-76
16354680
J Biol Chem. 1989 Jun 5;264(16):9657-64
2542317
Am J Physiol. 1999 Jul;277(1):E1-10
10409121
Mol Cell Biol. 1990 Feb;10(2):480-5
2300049
Mol Cell Biol. 1996 Feb;16(2):694-703
8552098
Nat Med. 2004 Jun;10(6):633-7
15146178
Biochem J. 2007 Nov 15;408(1):69-77
17696880
J Biol Chem. 1996 Jan 12;271(2):611-4
8557660
Mol Cell Biol. 2000 Sep;20(17):6508-17
10938127
Nature. 2001 Sep 13;413(6852):179-83
11557984
J Biol Chem. 2007 Mar 30;282(13):9482-9491
17277356
J Biol Chem. 2002 May 3;277(18):15629-37
11864972
Mol Cell. 2003 Aug;12(2):413-23
14536081
Annu Rev Biochem. 1997;66:581-611
9242918
Nat Med. 2002 Nov;8(11):1288-95
12368907
Diabetes. 2005 May;54(5):1331-9
15855317
J Biol Chem. 1984 Dec 25;259(24):15242-51
6096365
Curr Biol. 2004 Dec 14;14(23):2156-61
15589160
J Biol Chem. 1998 Jul 24;273(30):18743-50
9668047
Proc Natl Acad Sci U S A. 2003 Oct 14;100(21):12147-52
14506290
Eur J Biochem. 1988 Aug 1;175(2):331-8
2900138
Cell Signal. 2008 Mar;20(3):460-6
17993258
Cell Metab. 2006 Jun;3(6):403-16
16753576
Science. 2005 Dec 9;310(5754):1642-6
16308421
J Biol Chem. 1997 May 9;272(19):12868-73
9139749