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Monocarboxylic Acid Transport

Research output: Contribution to journalArticle

  • Andrew P. Halestrap
Original languageEnglish
Pages (from-to)1611-1643
Number of pages33
JournalComprehensive Physiology
Volume3
Issue number4
DOIs
DatePublished - Oct 2013

Abstract

Monocarboxylates such as lactate, pyruvate, and the ketone bodies play major roles in metabolism and must be transported across both the plasma membrane and mitochondrial inner membrane. A family of five proton-linked MonoCarboxylate Transporters (MCTs) is involved in the former and the mitochondrial pyruvate carrier (MPC) mediates the latter. In the intestine and kidney, two Sodium-coupled MonoCarboxylate Transporters (SMCTs) provide active transport of monocarboxylates across the apical membrane of the epithelial cells with MCTs on the basolateral membrane transporting the accumulated monocarboxylate into the blood. The kinetics and substrate and inhibitor specificities of MCTs, SMCTs, and the MPC have been well characterized and the molecular identity of the MCTs and SMCTs defined unequivocally. The identity of the MPC is less certain. The MCTs have been extensively studied and the three-dimensional structure of MCT1 has been modeled and a likely catalytic mechanism proposed. MCTs require the binding of a single transmembrane glycoprotein (either embigin or basigin) for activity. Regulation of MCT activity involves both transcriptional and posttranscriptional mechanisms, examples being upregulation of MCT1 by chronic exercise in red muscle (which oxidizes lactate) and in T-lymphocytes upon stimulation. MCT4 has properties that make it especially suited for lactic acid export by glycolytic cells and is upregulated by hypoxia. Some disease states are associated with modulation of plasma membrane and mitochondrial monocarboxylate transport and MCTs are promising drug targets for cancer chemotherapy. They may also be involved in drug uptake from the intestine and subsequent transport across the blood brain barrier. (C) 2013 American Physiological Society.

    Research areas

  • MITOCHONDRIAL PYRUVATE CARRIER, BORDER-MEMBRANE-VESICLES, L-LACTATE TRANSPORT, RETINAL-PIGMENT EPITHELIUM, RAT-LIVER MITOCHONDRIA, HUMAN SKELETAL-MUSCLE, ASCITES-TUMOR-CELLS, XENOPUS-LAEVIS OOCYTES, CARBONIC-ANHYDRASE II, INTRACELLULAR PH INDICATOR

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