Zp. Chen et al., AMPK signaling in contracting human skeletal muscle: acetyl-CoA carboxylase and NO synthase phosphorylation, AM J P-ENDO, 279(5), 2000, pp. E1202-E1206
Citations number
31
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
AMP-activated protein kinase (AMPK) is a metabolic stress-sensing protein k
inase responsible for coordinating metabolism and energy demand. In rodents
, exercise accelerates fatty acid metabolism, enhances glucose uptake, and
stimulates nitric oxide (NO) production in skeletal muscle. AMPK phosphoryl
ates and inhibits acetyl-coenzyme A (CoA) carboxylase (ACC) and enhances GL
UT-4 translocation. It has been reported that human skeletal muscle malonyl
-CoA levels do not change in response to exercise, suggesting that other me
chanisms besides inhibition of ACC may be operating to accelerate fatty aci
d oxidation. Here, we show that a 30-s bicycle sprint exercise increases th
e activity of the human skeletal muscle AMPK-alpha1 and -alpha2 isoforms ap
proximately two- to threefold and the phosphorylation of ACC at Ser(79) (AM
PK phosphorylation site) similar to8.5-fold. Under these conditions, there
is also an similar to5.5-fold increase in phosphorylation of neuronal NO sy
nthase-mu (nNOS mu) at Ser(1451). These observations support the concept th
at inhibition of ACC is an important component in stimulating fatty acid ox
idation in response to exercise and that there is coordinated regulation of
nNOS mu to protect the muscle from ischemia/metabolic stress.