Long-term regulation of AMP-activated protein kinase and acetyl-CoA carboxylase in skeletal muscle.
Evidence is accumulating for roles of AMP-activated protein kinase (AMPK) in controlling glucose uptake, fatty acid oxidation and gene expression in skeletal muscle. Relatively little is known, however, about the control of expression of the AMPK subunit isoforms. Marked differences are noted in subunit expression as a function of muscle fibre type. Expression of the gamma3 subunit isoform increases in fast-twitch red fibres of the rat in response to training. All subunit isoforms are expressed to a lesser extent in rats treated with propylthiouracil (PTU; an inhibitor of thyroid hormone synthesis) for 3 weeks compared with rats given excess thyroid hormones for 3 weeks. An approx. 2-fold increase in acetyl-CoA carboxylase was observed in gastrocnemius of hyperthyroid rats compared with experimentally hypothyroid rats. Thyroid state therefore appears to be one important factor controlling expression of these proteins in skeletal muscle.
Winder
W W
WW
Department of Physiology and Developmental Biology, 545 WIDB, Brigham Young University, Provo, UT 84602, USA. William_winder@byu.edu
Hardie
D G
DG
Mustard
K J
KJ
Greenwood
L J
LJ
Paxton
B E
BE
Park
S H
SH
Rubink
D S
DS
Taylor
E B
EB
D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D015971:Gene Expression Regulation, Enzymologic; D008099:Liver / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000378:metabolism; D020033:Protein Isoforms; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D013963:Thyroid Hormones / Q000378:metabolism; D013997:Time Factors
D009097:Multienzyme Complexes; D020033:Protein Isoforms; D013963:Thyroid Hormones; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase