Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Characterisation of human monocarboxylate transporter 4 substantiates its role in lactic acid efflux from skeletal muscle.
Manning Fox JE
,
Meredith D
,
Halestrap AP
.
???displayArticle.abstract???
Monocarboxylate transporter (MCT) 4 is the major monocarboxylate transporter isoform present in white skeletal muscle and is responsible for the efflux of lactic acid produced by glycolysis. Here we report the characterisation of MCT4 expressed in Xenopus oocytes. The protein was correctly targeted to the plasma membrane and rates of substrate transport were determined from the rate of intracellular acidification monitored with the pH-sensitive dye 2', 7'-bis-(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). In order to validate the technique, the kinetics of monocarboxylate transport were measured in oocytes expressing MCT1. Km values determined for L-lactate, D-lactate and pyruvate of 4.4, > 60 and 2.1 mM, respectively, were similar to those determined previously in tumour cells. Comparison of the time course of [14C]lactate accumulation with the rate of intracellular acidification monitored with BCECF suggests that the latter reflects pH changes close to the plasma membrane associated with transport, whilst the former may include diffusion-limited movement of lactate into the bulk cytosol. Km values of MCT4 for these substrates were found to be 28, 519 and 153 mM, respectively, and for a range of other monocarboxylates values were at least an order of magnitude higher than for MCT1. Vmax values appeared to be similar for all substrates. K0.5 values of MCT4 (determined at 30 mM L-lactate) for inhibition by alpha-cyano-4-hydroxycinnamate (991 microM), phloretin (41 microM), 5-nitro-2-(3-phenylpropylamino)benzoate (240 microM), p-chloromercuribenzene sulphonate (21 microM) and 3-isobutyl-1-methylxanthine (970 microM, partial inhibition) were also substantially higher than for MCT1. No inhibition of MCT4 by 2 mM 4,4'-diisothiocyanostilbene-2,2'-disulphonate was observed. The properties of MCT4 are consistent with published data on giant sarcolemmal vesicles in which MCT4 is the dominant MCT isoform, and are appropriate for the proposed role of MCT4 in mediating the efflux from the cell of glycolytically derived lactic acid but not pyruvate.
Bonen,
Lactate transport and lactate transporters in skeletal muscle.
1997, Pubmed
Bonen,
Lactate transport and lactate transporters in skeletal muscle.
1997,
Pubmed
Bonen,
Abundance and subcellular distribution of MCT1 and MCT4 in heart and fast-twitch skeletal muscles.
2000,
Pubmed
Bröer,
Comparison of lactate transport in astroglial cells and monocarboxylate transporter 1 (MCT 1) expressing Xenopus laevis oocytes. Expression of two different monocarboxylate transporters in astroglial cells and neurons.
1997,
Pubmed
,
Xenbase
Bröer,
Characterization of the monocarboxylate transporter 1 expressed in Xenopus laevis oocytes by changes in cytosolic pH.
1998,
Pubmed
,
Xenbase
Bröer,
Characterization of the high-affinity monocarboxylate transporter MCT2 in Xenopus laevis oocytes.
1999,
Pubmed
,
Xenbase
Carpenter,
The kinetics, substrate and inhibitor specificity of the lactate transporter of Ehrlich-Lettre tumour cells studied with the intracellular pH indicator BCECF.
1994,
Pubmed
Denton,
Regulation of pyruvate metabolism in mammalian tissues.
1979,
Pubmed
Garcia,
cDNA cloning of MCT2, a second monocarboxylate transporter expressed in different cells than MCT1.
1995,
Pubmed
Halestrap,
The proton-linked monocarboxylate transporter (MCT) family: structure, function and regulation.
1999,
Pubmed
,
Xenbase
Jackson,
The kinetics, substrate, and inhibitor specificity of the monocarboxylate (lactate) transporter of rat liver cells determined using the fluorescent intracellular pH indicator, 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein.
1996,
Pubmed
Juel,
Lactate-proton cotransport in skeletal muscle.
1997,
Pubmed
Juel,
Lactate transport in skeletal muscle - role and regulation of the monocarboxylate transporter.
1999,
Pubmed
Lin,
Human monocarboxylate transporter 2 (MCT2) is a high affinity pyruvate transporter.
1998,
Pubmed
McCullagh,
Chronic electrical stimulation increases MCT1 and lactate uptake in red and white skeletal muscle.
1997,
Pubmed
McCullagh,
Role of the lactate transporter (MCT1) in skeletal muscles.
1996,
Pubmed
Philp,
Monocarboxylate transporter MCT1 is located in the apical membrane and MCT3 in the basal membrane of rat RPE.
1998,
Pubmed
Pilegaard,
Effect of prior eccentric contractions on lactate/H+ transport in rat skeletal muscle.
1998,
Pubmed
Pilegaard,
Effect of high-intensity exercise training on lactate/H+ transport capacity in human skeletal muscle.
1999,
Pubmed
Pilegaard,
Distribution of the lactate/H+ transporter isoforms MCT1 and MCT4 in human skeletal muscle.
1999,
Pubmed
Poole,
Transport of lactate and other monocarboxylates across mammalian plasma membranes.
1993,
Pubmed
Price,
Cloning and sequencing of four new mammalian monocarboxylate transporter (MCT) homologues confirms the existence of a transporter family with an ancient past.
1998,
Pubmed
Sasaki,
Regulation mechanisms of intracellular pH of Xenopus laevis oocyte.
1992,
Pubmed
,
Xenbase
Walter,
Monocarboxylic acid permeation through lipid bilayer membranes.
1984,
Pubmed
Wang,
Kinetics of the sarcolemmal lactate carrier in single heart cells using BCECF to measure pHi.
1994,
Pubmed
Wang,
Substrate and inhibitor specificities of the monocarboxylate transporters of single rat heart cells.
1996,
Pubmed
Wilson,
Lactic acid efflux from white skeletal muscle is catalyzed by the monocarboxylate transporter isoform MCT3.
1998,
Pubmed
Yoon,
Identification of a unique monocarboxylate transporter (MCT3) in retinal pigment epithelium.
1997,
Pubmed
de Hemptinne,
Influence of organic acids on intracellular pH.
1983,
Pubmed