AMP activated protein kinase (AMPK) and p38 mitogen activated protein kinases (MAPKs) are activated during exercise and thought to be involved in mitochondrial biogenesis through activation of PGC-1α. AMPK is activated through an increase in AMP (Hardie et al. 1998) however the activation mechanisms of the isoforms of p38 MAPK are currently unknown in skeletal muscle. It is hypothesized that exercise induced energetic drain induces phosphorylation of AMPK specifically leading to downstream phosphorylation of the p38γ MAPK isoform. Inhibitors of the two major ATPases suggest that energetic drain, not calcium cycling or force production, leads to the phosphorylation of p38γ MAPK. Direct activation of AMPK using AICAR revealed AMPK is insufficient to significantly activate p38γ MAPK. 2-deoxyglucose had no effect on the activation of either AMPK or p38γ MAPK. Further studies need to be conducted to determine the signaling pathway for activation of mitochondrial biogenesis.
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