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AMPK phosphorylation of ACC2 is required for skeletal muscle fatty acid oxidation and insulin sensitivity in mice

O’Neill, Hayley M.
Lally, James S.
Galic, Sandra
Thomas, Melissa
Azizi, Paymon D.
Fullerton, Morgan D.
Smith, Brennan K.
Pulinilkunnil, Thomas
Chen, Zhiping
Constantine Samaan, M.
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Abstract
Aims/hypothesis: Obesity is characterised by lipid accumulation in skeletal muscle, which increases the risk of developing insulin resistance and type 2 diabetes. AMP-activated protein kinase (AMPK) is a sensor of cellular energy status and is activated in skeletal muscle by exercise, hormones (leptin, adiponectin, IL-6) and pharmacological agents (5-amino-4-imidazolecarboxamide ribonucleoside [AICAR] and metformin). Phosphorylation of acetyl-CoA carboxylase 2 (ACC2) at S221 (S212 in mice) by AMPK reduces ACC activity and malonyl-CoA content but the importance of the AMPK–ACC2–malonyl-CoA pathway in controlling fatty acid metabolism and insulin sensitivity is not understood; therefore, we characterised Acc2 S212A knock-in (ACC2 KI) mice. Methods: Whole-body and skeletal muscle fatty acid oxidation and insulin sensitivity were assessed in ACC2 KI mice and wild-type littermates. Results: ACC2 KI mice were resistant to increases in skeletal muscle fatty acid oxidation elicited by AICAR. These mice had normal adiposity and liver lipids but elevated contents of triacylglycerol and ceramide in skeletal muscle, which were associated with hyperinsulinaemia, glucose intolerance and skeletal muscle insulin resistance. Conclusions/interpretation: These findings indicate that the phosphorylation of ACC2 S212 is required for the maintenance of skeletal muscle lipid and glucose homeostasis.
Keywords
ACC2, AMPK, fatty acid oxidation, insulin resistance, knock-in mice, Malonyl-CoA, skeletal muscle
Date
2012
Type
Journal article
Journal
Diabetologia
Book
Volume
57
Issue
8
Page Range
1693-1702
Article Number
ACU Department
Faculty of Health Sciences
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Open Access Status
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File Access
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