Contractions induce phosphorylation of the AMPK site Ser565 in hormone-sensitive lipase in muscle |
| |
Authors: | Donsmark Morten Langfort Jozef Holm Cecilia Ploug Thorkil Galbo Henrik |
| |
Institution: | Copenhagen Muscle Research Centre, Department of Medical Physiology, The Panum Institute, University of Copenhagen, Denmark. mdonsmark@mfi.ku.dk |
| |
Abstract: | Intramyocellular triglyceride is an important energy store which is related to insulin resistance. Mobilization of fatty acids from this pool is probably regulated by hormone-sensitive lipase (HSL), which has recently been shown to exist in muscle and to be activated by epinephrine via PKA and by contractions via PKC and ERK. 5' AMP-activated protein kinase (AMPK) is an intracellular fuel gauge which regulates metabolism. In this study we incubated rat soleus muscle to investigate if AMPK influences HSL during 5min of repeated tetanic contractions. An eightfold increase in AMPK activity was accompanied by a 2.5-fold increase in phosphorylation of the AMPK-site Ser(565) in HSL (p<0.05). Inhibition of PKC by Calphostin C abolished the contraction-mediated HSL activation while HSL-Ser(565) phosphorylation was not reduced. The study indicates that during contractions AMPK phosphorylates HSL in Ser(565), but this phosphorylation is not directly responsible for the contraction-induced activation of HSL. |
| |
Keywords: | Triacylglycerol Lipolysis Metabolism Muscle Exercise Enzyme |
本文献已被 ScienceDirect PubMed 等数据库收录! |