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AICAR‐induced Activation of AMPK Causes Phosphorylation of p38 MAPK gamma in Resting Skeletal Muscle
Author(s) -
Brooks Ryan S,
Ankrapp David P,
Wiseman Robert W
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a819-c
Subject(s) - ampk , phosphorylation , p38 mitogen activated protein kinases , skeletal muscle , chemistry , protein kinase a , endocrinology , medicine , extensor digitorum longus muscle , activator (genetics) , microbiology and biotechnology , biology , biochemistry , gene
Activation of p38 MAPK correlates with muscle contraction but is not dependent upon mechanical force (Am J Physiol Cell Physiol., 288:C824–30, 2005). When energetic demands are inhibited in stimulated muscle, phosphorylation of p38γ, but not the α/β isoforms, is attenuated suggesting that p38γ is sensitive to energetic changes in muscle (2005 Experimental Biology, abstract# LB125). One likely candidate for transducing an energetic signal through p38γ is AMPK (FASEB J., 17:1658‐65, 2003), thus we tested the hypothesis that activation of AMPK induces phosphorylation of p38γ. Extensor digitorum longus (EDL) and soleus (SOL) muscles from male Swiss Webster mice were excised and fixed at resting length in serum‐supplemented medium at 35°C for 24 hours with and without 0.5 mM AICAR (AMPK activator). Relative to untreated muscle, AMPK phosphorylation increased six‐ and fourteen‐fold in AICAR‐treated EDL and SOL, respectively. Moreover, phosphorylation of p38γ increased four‐fold only in AICAR‐treated EDL and SOL, whereas phosphorylation of p38α/β did not change with treatment. Our data suggests that phosphorylation of p38γ is dependent upon activation of AMPK and thus may play a key role in AMPK‐mediated signaling in skeletal muscle in response to changes in energetic demand. Supported by NSBRI MA‐00210, MSU IRPG 41006 and the Department of Radiology at MSU.