CaMKK is an upstream signal of AMP-activated protein kinase in regulation of substrate metabolism in contracting skeletal muscle

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2009-12, Vol.297 (6), p.R1724-R1732
• Main Authors: Abbott, Marcia J, Edelman, Arthur M, Turcotte, Lorraine P
• Format: Article
• Language: English
• Subjects: Aminoimidazole Carboxamide - analogs & derivatives; Aminoimidazole Carboxamide - pharmacology; AMP-Activated Protein Kinases - metabolism; Animals; Benzimidazoles - pharmacology; Caffeine; Caffeine - pharmacology; Calcium Signaling; Calcium-Calmodulin-Dependent Protein Kinase Kinase - antagonists & inhibitors; Calcium-Calmodulin-Dependent Protein Kinase Kinase - metabolism; CD36 Antigens - metabolism; Energy Metabolism; Enzyme Activation; Enzyme Activators - pharmacology; Fatty acids; Glucose; Glucose - metabolism; Glucose Transporter Type 4 - metabolism; Hindlimb; Kinases; Male; Metabolism; Muscle Contraction; Muscle, Skeletal - enzymology; Musculoskeletal system; Naphthalimides - pharmacology; Oxidation; Oxidation-Reduction; Oxygen Consumption; Palmitic Acid - metabolism; Perfusion; Phosphorylation; Protein Kinase Inhibitors - pharmacology; Rats; Rats, Wistar; Ribonucleotides - pharmacology; Rodents
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00179.2009

1 Department of Kinesiology and 2 Department of Biological Sciences, College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, California; and 3 Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York Submitted March 27, 2009 ; accepted in final form October 1, 2009 Multiple signals have been shown to be involved in regulation of fatty acid (FA) and glucose metabolism in contracting skeletal muscle. This study aimed to determine whether a Ca 2+ -stimulated kinase, CaMKK, is involved in regulation of contraction-induced substrate metabolism and whether it does so in an AMP-activated protein kinase (AMPK)-dependent manner. Rat hindlimbs were perfused at rest ( n = 16), with 3 mM caffeine ( n = 15), with 2 mM 5-aminoimidazole-4-carboxamide 1-β- D -ribofuranoside (AICAR; n = 16), or during moderate-intensity muscle contraction (MC; n = 14) and with or without 5 µM STO-609, a CaMKK inhibitor. FA uptake and oxidation increased ( P < 0.05) 64% and 71% by caffeine, 42% and 93% by AICAR, and 65% and 143% by MC. STO-609 abolished ( P < 0.05) caffeine- and MC-induced FA uptake and oxidation but had no effect with AICAR treatment. Glucose uptake increased ( P < 0.05) 104% by caffeine, 85% by AICAR, and 130% by MC, and STO-609 prevented the increase in glucose uptake in caffeine and muscle contraction groups. CaMKKβ activity increased ( P < 0.05) 113% by caffeine treatment and 145% by MC but was not affected by AICAR treatment. STO-609 prevented the caffeine- and MC-induced increase in CaMKKβ activity. Caffeine, AICAR, and MC increased ( P < 0.05) AMPK 2 activity by 295%, 11-fold, and 7-fold but did not affect AMPK 1 activity. STO-609 decreased ( P < 0.05) AMPK 2 activity induced by caffeine treatment and MC by 60% and 61% but did not affect AICAR-induced activity. Plasma membrane transport protein content of CD36 and glucose transporter 4 (GLUT4) increased ( P < 0.05) with caffeine, AICAR, and MC, and STO-609 prevented caffeine- and MC-induced increases in protein content. These results show the importance of Ca 2+ -dependent signaling via CaMKK activation in the regulation of substrate uptake and FA oxidation in contracting rat skeletal muscle and agree with the notion that CaMKK is an upstream kinase of AMPK in the regulation of substrate metabolism in skeletal muscle. fatty acid oxidation; 5-aminoimidazole-4-carboxamide 1-β- D -ribofuranoside; STO-609; fatty acid translocase/CD36; Glut-4 Address for r