Document Detail

Energy sensing by the AMP-activated protein kinase and its effects on muscle metabolism.
MedLine Citation:
PMID:  21067629     Owner:  NLM     Status:  MEDLINE    
The AMP-activated protein kinase (AMPK) is a sensor of cellular energy status, and a regulator of energy balance at both the cellular and whole body levels. Although ubiquitously expressed, its function is best understood in skeletal muscle. AMPK contains sites that reversibly bind AMP or ATP, with an increase in cellular AMP:ATP ratio (signalling a fall in cellular energy status) switching on the kinase. In muscle, AMPK activation is therefore triggered by sustained contraction, and appears to be particularly important in the metabolic changes that occur in the transition from resistance to endurance exercise. Once activated, AMPK switches on catabolic processes that generate ATP, while switching off energy-requiring processes not essential in the short term. Thus, it acutely activates glucose uptake (by promoting translocation of the transporter GLUT4 to the membrane) and fatty acid oxidation, while switching off glycogen synthesis and protein synthesis (the later via inactivation of the mammalian target-of-rapamycin pathway). Prolonged AMPK activation also causes some of the chronic adaptations to endurance exercise, such as increased GLUT4 expression and mitochondrial biogenesis. AMPK contains a glycogen-binding domain that causes a sub-fraction to bind to the surface of the glycogen particle, and it can inhibit glycogen synthesis by phosphorylating glycogen synthase. We have shown that AMPK is inhibited by exposed non-reducing ends in glycogen. We are working on the hypothesis that this ensures that glycogen synthesis is rapidly activated when glycogen becomes depleted after exercise, but is switched off again as soon as glycogen stores are replenished.
D Grahame Hardie
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review     Date:  2010-11-11
Journal Detail:
Title:  The Proceedings of the Nutrition Society     Volume:  70     ISSN:  1475-2719     ISO Abbreviation:  Proc Nutr Soc     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-26     Completed Date:  2011-07-21     Revised Date:  2013-04-24    
Medline Journal Info:
Nlm Unique ID:  7505881     Medline TA:  Proc Nutr Soc     Country:  England    
Other Details:
Languages:  eng     Pagination:  92-9     Citation Subset:  IM    
College of Life Sciences, University of Dundee, Dundee, UK.
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MeSH Terms
AMP-Activated Protein Kinases / chemistry,  metabolism*
Adenosine Monophosphate / metabolism
Adenosine Triphosphate / metabolism
Energy Metabolism*
Exercise / physiology*
Glucose / metabolism*
Glycogen / biosynthesis*
Lipid Metabolism*
Muscle Contraction / physiology
Muscle Proteins / biosynthesis
Muscle, Skeletal / metabolism*
Signal Transduction
Reg. No./Substance:
0/Muscle Proteins; 50-99-7/Glucose; 56-65-5/Adenosine Triphosphate; 61-19-8/Adenosine Monophosphate; 9005-79-2/Glycogen; EC Protein Kinases

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