Anja Vidović, Klemen Dolinar, Alexander V Chibalin, Sergej Pirkmajer
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引用次数: 0
Abstract
In skeletal muscle, Na+,K+-ATPase (NKA), a heterodimeric (α/β) P-type ATPase, has an essential role in maintenance of Na+ and K+ homeostasis, excitability, and contractility. AMP-activated protein kinase (AMPK), an energy sensor, increases the membrane abundance and activity of NKA in L6 myotubes, but its potential role in regulation of NKA content in skeletal muscle, which determines maximum capacity for Na+ and K+ transport, has not been clearly delineated. We examined whether energy stress and/or AMPK affect expression of NKA subunits in rat L6 and primary human myotubes. Energy stress, induced by glucose deprivation, increased protein content of NKAα1 and NKAα2 in L6 myotubes, while decreasing the content of NKAα1 in human myotubes. Pharmacological AMPK activators (AICAR, A-769662, and diflunisal) modulated expression of NKA subunits, but their effects only partially mimicked those that occurred in response to glucose deprivation, indicating that AMPK does not mediate all effects of energy stress on NKA expression. Gene silencing of AMPKα1/α2 increased protein levels of NKAα1 in L6 myotubes and NKAα1 mRNA levels in human myotubes, while decreasing NKAα2 protein levels in L6 myotubes. Collectively, our results suggest a role for energy stress and AMPK in modulation of NKA expression in skeletal muscle. However, their modulatory effects were not conserved between L6 myotubes and primary human myotubes, which suggests that coupling between energy stress, AMPK, and regulation of NKA expression in vitro depends on skeletal muscle cell model.
期刊介绍:
The Journal of Muscle Research and Cell Motility has as its main aim the publication of original research which bears on either the excitation and contraction of muscle, the analysis of any one of the processes involved therein, the processes underlying contractility and motility of animal and plant cells, the toxicology and pharmacology related to contractility, or the formation, dynamics and turnover of contractile structures in muscle and non-muscle cells. Studies describing the impact of pathogenic mutations in genes encoding components of contractile structures in humans or animals are welcome, provided they offer mechanistic insight into the disease process or the underlying gene function. The policy of the Journal is to encourage any form of novel practical study whatever its specialist interest, as long as it falls within this broad field. Theoretical essays are welcome provided that they are concise and suggest practical ways in which they may be tested. Manuscripts reporting new mutations in known disease genes without validation and mechanistic insight will not be considered. It is the policy of the journal that cells lines, hybridomas and DNA clones should be made available by the developers to any qualified investigator. Submission of a manuscript for publication constitutes an agreement of the authors to abide by this principle.