Oxidative stress induces GLUT4 translocation by activation of PI3-K/Akt and dual AMPK kinase in cardiac myocytes.
In response to metabolic stress, GLUT4, the most abundant glucose transporter, translocates from intracellular vesicles to the plasma membrane. This appears to play an important role in protecting cardiac myocytes from ischemic injury. To investigate the precise mechanisms of GLUT4 translocation in cardiomyocytes, we have established a method for quantifying the relative proportion of sarcolemmal GLUT4 to total GLUT4 in these cells. Stimulation with H2O2 resulted in a concentration-dependent increase in GLUT4 translocation, which peaked at 15 min after stimulation. The dominant-negative form (DN) of AMP-activated protein kinase (AMPK) alpha2 inhibited the H2O2-induced translocation of GLUT4. We further examined the role of two known AMPK kinases (AMPKKs), calmodulin-dependent protein kinase kinase (CaMKK)beta and LKB1. The DN of CaMKKbeta or LKB1 alone inhibited H2O2-induced GLUT4 translocation only partially compared to the inhibition produced by the DN of AMPKalpha2. However, the combination of DN-LKB1 and DN-CaMKKbeta inhibited translocation to an extent similar to with DN-AMPKalpha2. Stimulation with H2O2 also activated Akt and the inhibition of PI3-K/Akt prevented GLUT4 translocation to the same extent as with AMPK inhibition. When the DN of AMPKalpha2 was applied with DN-PI3-K, there was a complete reduction in the GLUT4 membrane level similar to that seen at the 0 time-point. These results demonstrate that AMPK and PI3-K/Akt have an additive effect on oxidative stress-mediated GLUT4 translocation.
Horie
Takahiro
T
Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Ono
Koh
K
Nagao
Kazuya
K
Nishi
Hitoo
H
Kinoshita
Minako
M
Kawamura
Teruhisa
T
Wada
Hiromichi
H
Shimatsu
Akira
A
Kita
Toru
T
Hasegawa
Koji
K
D055372:AMP-Activated Protein Kinases; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009097:Multienzyme Complexes / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D018384:Oxidative Stress / Q000187:drug effects; D030421:Peroxynitrous Acid / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats
D055372:AMP-Activated Protein Kinases; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D002118:Calcium; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D051275:Glucose Transporter Type 4; D006861:Hydrogen Peroxide; D007328:Insulin; D009097:Multienzyme Complexes; D030421:Peroxynitrous Acid; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; C491654:Stk11 protein, mouse