Cardiac and skeletal muscle mitochondria have a monocarboxylate transporter MCT1.
To evaluate the potential role of monocarboxylate transporter-1 (MCT1) in tissue lactate oxidation, isolated rat subsarcolemmal and interfibrillar cardiac and skeletal muscle mitochondria were probed with an antibody to MCT1. Western blots indicated presence of MCT1 in sarcolemmal membranes and in subsarcolemmal and interfibrillar mitochondria. Minimal cross-contamination of mitochondria by cell membrane fragments was verified by probing for the sarcolemmal protein GLUT-1. In agreement, immunolabeling and electron microscopy showed mitochondrial MCT1 in situ. Along with lactic dehydrogenase, the presence of MCT1 in striated muscle mitochondria permits mitochondrial lactate oxidation and facilitates function of the "intracellular lactate shuttle."
Brooks
G A
GA
Exercise Physiology Laboratory, Department of Integrative Biology, University of California, Berkeley, California 94720-3140, USA. Gbrooks@Socrates.Berkeley.Edu
Brown
M A
MA
Butz
C E
CE
Sicurello
J P
JP
Dubouchaud
H
H
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D051272:Glucose Transporter Type 1; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008854:Microscopy, Electron; D008931:Mitochondria, Muscle / Q000378:metabolism*; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009210:Myofibrils / Q000378:metabolism; D019289:Pyruvic Acid / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000378:metabolism
D000906:Antibodies; D002352:Carrier Proteins; D051272:Glucose Transporter Type 1; D027501:Monocarboxylic Acid Transporters; D009004:Monosaccharide Transport Proteins; C495679:Slc2a1 protein, rat; D019344:Lactic Acid; D019289:Pyruvic Acid; D007770:L-Lactate Dehydrogenase