Acute regulation of fatty acid uptake involves the cellular redistribution of fatty acid translocase.
We used muscle contraction, which increases fatty acid oxidation, as a model to determine whether fatty acid transport is acutely regulated by fatty acid translocase (FAT/CD36). Palmitate uptake by giant vesicles, obtained from skeletal muscle, was increased by muscle contraction. Kinetic studies indicated that muscle contraction increased V(max), but K(m) remained unaltered. Sulfo-N-succinimidyl oleate, a specific inhibitor of FAT/CD36, fully blocked the contraction-induced increase in palmitate uptake. In giant vesicles from contracting muscles, plasma membrane FAT/CD36 was also increased in parallel with the increase in long chain fatty acid uptake. Further studies showed that like GLUT-4, FAT/CD36 is located in both the plasma membrane and intracellularly (endosomally). With muscle contraction, FAT/CD36 at the surface of the muscle was increased, while concomitantly, FAT/CD36 in the intracellular pool was reduced. Similar responses were observed for GLUT-4. We conclude that fatty acid uptake is subject to short term regulation by muscle contraction and involves the translocation of FAT/CD36 from intracellular stores to the sarcolemma, analogous to the regulation of glucose uptake by GLUT-4.
Bonen
A
A
Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. abonen@healthy.uwaterloo.ca
Luiken
J J
JJ
Arumugam
Y
Y
Glatz
J F
JF
Tandon
N N
NN
D000818:Animals; D018955:CD36 Antigens / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009119:Muscle Contraction; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism; D027361:Organic Anion Transporters; D019308:Palmitic Acid / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018955:CD36 Antigens; D051275:Glucose Transporter Type 4; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D027361:Organic Anion Transporters; C495694:Slc2a4 protein, rat; D019308:Palmitic Acid; D005947:Glucose