AMPK signaling in contracting human skeletal muscle: acetyl-CoA carboxylase and NO synthase phosphorylation.

AMP-activated protein kinase (AMPK) is a metabolic stress-sensing protein kinase responsible for coordinating metabolism and energy demand. In rodents, exercise accelerates fatty acid metabolism, enhances glucose uptake, and stimulates nitric oxide (NO) production in skeletal muscle. AMPK phosphorylates and inhibits acetyl-coenzyme A (CoA) carboxylase (ACC) and enhances GLUT-4 translocation. It has been reported that human skeletal muscle malonyl-CoA levels do not change in response to exercise, suggesting that other mechanisms besides inhibition of ACC may be operating to accelerate fatty acid oxidation. Here, we show that a 30-s bicycle sprint exercise increases the activity of the human skeletal muscle AMPK-alpha1 and -alpha2 isoforms approximately two- to threefold and the phosphorylation of ACC at Ser(79) (AMPK phosphorylation site) approximately 8.5-fold. Under these conditions, there is also an approximately 5.5-fold increase in phosphorylation of neuronal NO synthase-mu (nNOSmu;) at Ser(1451). These observations support the concept that inhibition of ACC is an important component in stimulating fatty acid oxidation in response to exercise and that there is coordinated regulation of nNOSmu to protect the muscle from ischemia/metabolic stress.

[1]  R. Veech,et al.  Effects of pH and free Mg2+ on the Keq of the creatine kinase reaction and other phosphate hydrolyses and phosphate transfer reactions. , 1979, The Journal of biological chemistry.

[2]  M. Reid,et al.  Role of nitric oxide in skeletal muscle: synthesis, distribution and functional importance. , 1998, Acta physiologica Scandinavica.

[3]  T. Balon.  Role of nitric oxide in contraction induced glucose transport. , 1998, Advances in experimental medicine and biology.

[4]  E. Hultman,et al.  Glycogen, glycolytic intermediates and high-energy phosphates determined in biopsy samples of musculus quadriceps femoris of man at rest. Methods and variance of values. , 1974, Scandinavian journal of clinical and laboratory investigation.

[5]  Tatsuya Hayashi,et al.  Evidence for 5′AMP-Activated Protein Kinase Mediation of the Effect of Muscle Contraction on Glucose Transport , 1998, Diabetes.

[6]  M. Prentki,et al.  Activation of Malonyl-CoA Decarboxylase in Rat Skeletal Muscle by Contraction and the AMP-activated Protein Kinase Activator 5-Aminoimidazole-4-carboxamide-1-β-d-ribofuranoside* , 2000, The Journal of Biological Chemistry.

[7]  B. Kingwell,et al.  Nitric oxide synthase inhibition reduces leg glucose uptake but not blood flow during dynamic exercise in humans. , 1999, Diabetes.

[8]  Demetrios Vavvas,et al.  Malonyl-CoA, fuel sensing, and insulin resistance. , 1999, American journal of physiology. Endocrinology and metabolism.

[9]  Willlam W. Winder.  5 Malonyl‐CoA—Regulator of Fatty Acid Oxidation in Muscle During Exercise , 1998, Exercise and sport sciences reviews.

[10]  B. Saltin,et al.  Nitric oxide in the regulation of vasomotor tone in human skeletal muscle. , 1999, American journal of physiology. Heart and circulatory physiology.

[11]  H. Schmidt,et al.  Endothelial Nitric-oxide Synthase (Type III) Is Activated and Becomes Calcium Independent upon Phosphorylation by Cyclic Nucleotide-dependent Protein Kinases* , 2000, The Journal of Biological Chemistry.

[12]  O. Ljungqvist,et al.  Exercise induces isoform-specific increase in 5'AMP-activated protein kinase activity in human skeletal muscle. , 2000, Biochemical and biophysical research communications.

[13]  M. McKenna,et al.  Effect of creatine supplementation on sprint exercise performance and muscle metabolism. , 1998, Journal of applied physiology.

[14]  W. Sessa,et al.  Regulation of endothelium-derived nitric oxide production by the protein kinase Akt , 1999, Nature.

[15]  B. Kemp,et al.  Contraction-induced Changes in Acetyl-CoA Carboxylase and 5′-AMP-activated Kinase in Skeletal Muscle* , 1997, The Journal of Biological Chemistry.

[16]  R. Busse,et al.  Activation of nitric oxide synthase in endothelial cells by Akt-dependent phosphorylation , 1999, Nature.

[17]  D. Hardie,et al.  AICA riboside increases AMP-activated protein kinase, fatty acid oxidation, and glucose uptake in rat muscle. , 1997, American journal of physiology. Endocrinology and metabolism.

[18]  P. Ortiz de Montellano,et al.  AMP‐activated protein kinase phosphorylation of endothelial NO synthase , 1999, FEBS letters.

[19]  P. Jakeman,et al.  Determination of human skeletal muscle buffer value by homogenate technique: methods of measurement. , 1993, Journal of applied physiology.

[20]  R. Aebersold,et al.  Identification of Flow-dependent Endothelial Nitric-oxide Synthase Phosphorylation Sites by Mass Spectrometry and Regulation of Phosphorylation and Nitric Oxide Production by the Phosphatidylinositol 3-Kinase Inhibitor LY294002* , 1999, The Journal of Biological Chemistry.

[21]  D. Carling,et al.  Evidence that the AMP‐activated protein kinase stimulates rat liver carnitine palmitoyltransferase I by phosphorylating cytoskeletal components , 1998, FEBS letters.

[22]  M. Carlson,et al.  The AMP-activated/SNF1 protein kinase subfamily: metabolic sensors of the eukaryotic cell? , 1998, Annual review of biochemistry.

[23]  G. Maréchal,et al.  Effects of nitric oxide on the contraction of skeletal muscle , 1999, Cellular and Molecular Life Sciences CMLS.

[24]  L. Goodyear,et al.  5' AMP-activated protein kinase activation causes GLUT4 translocation in skeletal muscle. , 1999, Diabetes.

[25]  J. Passonneau,et al.  A comparison of three methods of glycogen measurement in tissues. , 1974, Analytical biochemistry.

[26]  G. Shulman,et al.  Translocation of myocardial GLUT-4 and increased glucose uptake through activation of AMPK by AICAR. , 1999, The American journal of physiology.

[27]  R. A. Howlett,et al.  Skeletal muscle malonyl-CoA content at the onset of exercise at varying power outputs in humans. , 1998, American journal of physiology. Endocrinology and metabolism.

[28]  J. E. Griffiths,et al.  The Akt kinase signals directly to endothelial nitric oxide synthase , 1999, Current Biology.

[29]  D. Bredt,et al.  Neuronal Nitric-oxide Synthase-, an Alternatively Spliced Isoform Expressed in Differentiated Skeletal Muscle (*) , 1996, The Journal of Biological Chemistry.