Inhibition of mitochondrial respiration by nitric oxide rapidly stimulates cytoprotective GLUT3-mediated glucose uptake through 5'-AMP-activated protein kinase.
Recently, we have reported that the inhibition of mitochondrial respiration by nitric oxide (NO) leads to an up-regulation of glycolysis and affords cytoprotection against energy failure through the stimulation of AMPK (5'-AMP-activated protein kinase) [Almeida, Moncada and Bolanos (2004) Nat. Cell Biol. 6, 45-51]. To determine whether glucose transport contributes specifically to this effect, we have now investigated the possible role of NO in modulating glucose uptake through GLUT3, a facilitative high-affinity glucose carrier that has been suggested to afford cytoprotection against hypoglycaemic episodes. To do so, GLUT3-lacking HEK-293T cells (human embryonic kidney 293T cells) were transformed to express a plasmid construction encoding green fluorescent protein-tagged GLUT3 cDNA. This carrier was preferentially localized to the plasma membrane, was seen to be functionally active and afforded cytoprotection against low glucose-induced apoptotic death. Inhibition of mitochondrial respiration by NO triggered a rapid, cGMP-independent enhancement of GLUT3-mediated glucose uptake through a mechanism that did not involve transporter translocation. Furthermore, the functional disruption of AMPK by the RNA interference strategy rendered cells unable to respond to NO by activating GLUT3-mediated glucose uptake. These results suggest that the inhibition of mitochondrial respiration by NO activates AMPK to stimulate glucose uptake, thereby representing a novel survival pathway during pathophysiological conditions involving transient reductions in the supply of cellular glucose.
Cidad
Pilar
P
Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain.
Almeida
Angeles
A
Bolaños
Juan P
JP
D055372:AMP-Activated Protein Kinases; D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D019069:Cell Respiration; D006152:Cyclic GMP / Q000378:metabolism; D019610:Cytoprotection; D005947:Glucose / Q000378:metabolism*; D051274:Glucose Transporter Type 3; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D010101:Oxygen Consumption; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats
D051274:Glucose Transporter Type 3; D009004:Monosaccharide Transport Proteins; D009097:Multienzyme Complexes; D009419:Nerve Tissue Proteins; C495687:SLC2A3 protein, human; C495690:Slc2a3 protein, rat; D009569:Nitric Oxide; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D006152:Cyclic GMP; D005947:Glucose