Sequential changes in the signal transduction responses of skeletal muscle following food deprivation.
Coping with reduced energy sources entails drastic morphological and functional changes in skeletal muscle, but the sequence of events required classification. We found that gastrocnemius muscle from food-deprived rats shows acute rises in peroxisome proliferator activated receptor (PPAR) gamma coactivator (PGC) -1alpha/PPAR delta nuclear protein and myosin heavy chain (MHC) Ib protein, while type I fibers accumulate and the muscle tissue appears redder. AMP levels, phosphorylation of both AMP-activated protein kinase (AMPK) and its downstream target acetyl coenzyme A carboxylase (ACC) are induced within 6 h. Rapidly increased MyoD mRNA levels are followed by an increase in uncoupling protein (UCP) 3 (UCP3) transcription. Increased serum fatty acid levels coincide with increases in mitochondrial UCP3 protein levels and fatty acid oxidation. Accompanying this is a decrease in AMPK phosphorylation, reversible upon nicotinic acid treatment, indicating that fatty acids may modulate this kinase's activity after the metabolic challenges posed by food deprivation.
de Lange
Pieter
P
Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100, Caserta, Italy.
Farina
Paola
P
Moreno
Maria
M
Ragni
Maurizio
M
Lombardi
Assunta
A
Silvestri
Elena
E
Burrone
Lavinia
L
Lanni
Antonia
A
Goglia
Fernando
F
D055372:AMP-Activated Protein Kinases; D000222:Adaptation, Physiological; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D005508:Food Deprivation / Q000502:physiology*; D005786:Gene Expression Regulation; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D017570:MyoD Protein / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000378:metabolism; D047494:PPAR delta / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
D009097:Multienzyme Complexes; D017570:MyoD Protein; D047494:PPAR delta; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C501429:Ppargc1a protein, rat; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D018995:Myosin Heavy Chains