Munc18c is not rate-limiting for glucose and long-chain fatty acid uptake in the heart.
The role of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)- and SNARE-associated proteins have not yet been assessed in regulation of cardiac glucose uptake, nor in the regulation of long-chain fatty acid (LCFA) uptake in any tissue. Munc18c is a SNARE-associated protein that regulates GLUT4 translocation in skeletal muscle and adipose tissue. Using cardiomyocytes from Munc18c(-/+) mice (with 56% reduction of Munc18c protein expression), we investigated whether this syntaxin4-associated protein is involved in regulation of cardiac substrate uptake. Basal, insulin- and oligomycin (a 5' AMP-activated protein kinase-activating agent)-stimulated glucose and LCFA uptake were not altered significantly in Munc18c(-/+) cardiomyocytes compared to wild-type cells. We conclude, therefore, that Munc18c is not rate-limiting for cardiac substrate uptake, neither under basal conditions nor when maximally stimulated metabolically.
Habets
Daphna D J
DD
Department of Molecular Genetics, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands. d.habets@gen.unimaas.nl
Thurmond
Debbie C
DC
Coumans
Will A
WA
Bonen
Arend
A
Glatz
Jan F C
JF
Luiken
Joost J F P
JJ
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D017252:CD3 Complex / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D007328:Insulin / Q000031:analogs & derivatives / Q000378:metabolism; D049528:Insulin, Long-Acting; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D051938:Munc18 Proteins / Q000235:genetics* / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism
D017252:CD3 Complex; D005230:Fatty Acids, Nonesterified; D051275:Glucose Transporter Type 4; D007328:Insulin; D049528:Insulin, Long-Acting; D051938:Munc18 Proteins; C497943:Stxbp3 protein, mouse; D055372:AMP-Activated Protein Kinases; D005947:Glucose