title: Exercise increases nuclear AMPK alpha2 in human skeletal muscle.
abstract: An acute bout of exercise increases skeletal muscle glucose uptake, improves glucose homeostasis and insulin sensitivity, and enhances muscle oxidative capacity. Recent studies have shown an association between these adaptations and the energy-sensing 5' AMP-activated protein kinase (AMPK), the activity of which is increased in response to exercise. Activation of AMPK has been associated with enhanced expression of key metabolic proteins such as GLUT-4, hexokinase II (HKII), and mitochondrial enzymes, similar to exercise. It has been hypothesized that AMPK might regulate gene and protein expression through direct interaction with the nucleus. The purpose of this study was to determine if nuclear AMPK alpha(2) content in human skeletal muscle was increased by exercise. Following 60 min of cycling at 72 +/- 1% of VO(2peak) in six male volunteers (20.6 +/- 2.1 years; 72.9 +/- 2.1 kg; VO(2peak) = 3.62 +/- 0.18 l/min), nuclear AMPK alpha(2) content was increased 1.9 +/- 0.4-fold (P = 0.024). There was no change in whole-cell AMPK alpha(2) content or AMPK alpha(2) mRNA abundance. These results suggest that nuclear translocation of AMPK might mediate the effects of exercise on skeletal muscle gene and protein expression.
authors.affiliation: Exercise, Muscle and Metabolism Unit, School of Health Sciences, Deakin University, Burwood, Australia.
authors.forename: Sean L
authors.initials: SL
authors.lastname: McGee
authors.forename: Kirsten F
authors.initials: KF
authors.lastname: Howlett
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Starkie
authors.forename: David
authors.initials: D
authors.lastname: Cameron-Smith
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Kemp
authors.forename: Mark
authors.initials: M
authors.lastname: Hargreaves
mesh_terms: D055372:AMP-Activated Protein Kinases; D000328:Adult; D002467:Cell Nucleus / Q000201:enzymology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D009097:Multienzyme Complexes / Q000032:analysis* / Q000235:genetics; D018482:Muscle, Skeletal / Q000201:enzymology / Q000648:ultrastructure*; D010101:Oxygen Consumption; D017346:Protein Serine-Threonine Kinases / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D013997:Time Factors
chemical_list: D009097:Multienzyme Complexes; D012333:RNA, Messenger; C526181:PRKAA2 protein, human; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases