Contractions induce phosphorylation of the AMPK site Ser565 in hormone-sensitive lipase in muscle.

TY - JOUR

T1 - Contractions induce phosphorylation of the AMPK site Ser565 in hormone-sensitive lipase in muscle.

AU - Donsmark, Morten

AU - Langfort, Jozef

AU - Holm, Cecilia

AU - Ploug, Thorkil

AU - Galbo, Henrik

N1 - Keywords: Animals; Binding Sites; Blotting, Western; Cyclic AMP-Dependent Protein Kinases; Epinephrine; Male; Mitogen-Activated Protein Kinases; Multienzyme Complexes; Muscle Contraction; Muscle, Skeletal; Naphthalenes; Phosphorylation; Protein Kinase C; Protein-Serine-Threonine Kinases; Rats; Rats, Wistar; Serine; Sterol Esterase; Time Factors; Triglycerides

PY - 2004

Y1 - 2004

N2 - 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.

AB - 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.

U2 - 10.1016/j.bbrc.2004.02.140

DO - 10.1016/j.bbrc.2004.02.140

M3 - Journal article

C2 - 15033481

SN - 0006-291X

VL - 316

SP - 867

EP - 871

JO - Biochemical and Biophysical Research Communications

JF - Biochemical and Biophysical Research Communications

IS - 3

ER -