Monocarboxylate transporter 1 is a ubiquitous protein that in humans is encoded by the SLC16A1 gene (also known as MCT1). [5] [6] [7] It is a proton coupled monocarboxylate transporter.
Monocarboxylate transporter 1 is a ubiquitous protein that in humans is encoded by the SLC16A1 gene (also known as MCT1). [5] [6] [7] It is a proton coupled monocarboxylate transporter.
Detailed kinetic analysis of monocarboxylate transport in erythrocytes revealed that MCT1 operates through an ordered mechanism. MCT1 has a substrate binding site open to the extracellular matrix which binds a proton first followed by the lactate anion. The protein then undergoes a conformational change to a new ‘closed’’ conformation that exposes both the proton and lactate to the opposite surface of the membrane where they are released, lactate first and then the proton. For net transport of lactic acid, the rate-limiting step is the return of MCT1 without bound substrate to the open conformation. For this reason, exchange of one monocarboxylate inside the cell with another outside is considerably faster than net transport of a monocarboxylate across the membrane.
MCT1 can be upregulated by PPAR-α, Nrf2, and AMPK. [8]
Overexpression of MCT1 has been shown to increase the efficacy of an anti-cancer drug currently undergoing clinical trials called 3-bromopyruvate in breast cancer cells. [9]
Most cases of alveolar soft part sarcoma show PAS(+), diastase-resistant (PAS-D (+)) intracytoplasmic crystals which contain CD147 and monocarboxylate transporter 1 (MCT1). [10] Overexpression of MCT1 in pancreatic beta cells leads to hyperinsulinism during exercise. [11]
Hyperinsulinemic hypoglycemia, familial, 7 (HHF7) is an autosomal dominant disease on the SLC16A1/MCT gene on chromosome 1p13.2. It causes hyperinsulinemic hypoglycemia, where hyperinsulinism is exercise-induced. [12]
Monocarboxylate transporter 1 deficiency (MCTD1) is an autosomal dominant and recessive disease on the SLC16A1/MCT1 gene on chromosome 1p13.2. It causes poor feeding and vomiting, intellectual disability, ketotic hypoglycemia, ketoacidosis, ketonuria, with episodes brought on by fasting or infection. [13]
Erythrocyte lactate transporter defect (formerly, myopathy due to lactate transport defect) is an autosomal dominant disease on the SLC16A1/MCT gene on chromosome 1p.13.2. It causes exercise-induced muscle cramping, stiffness, and fatigue (exercise intolerance); symptoms may also be induced by heat. Although symptoms present in the muscles, muscle biopsy and EMG are normal. Decreased erythrocyte (red blood cell) lactate clearance, decreased lactate clearance from muscle after exercise, and elevated serum creatine kinase. [14]
Cotransporters are a subcategory of membrane transport proteins (transporters) that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient. They enable coupled or cotransport and include antiporters and symporters. In general, cotransporters consist of two out of the three classes of integral membrane proteins known as transporters that move molecules and ions across biomembranes. Uniporters are also transporters but move only one type of molecule down its concentration gradient and are not classified as cotransporters.
Glucose transporter 1, also known as solute carrier family 2, facilitated glucose transporter member 1 (SLC2A1), is a uniporter protein that in humans is encoded by the SLC2A1 gene. GLUT1 facilitates the transport of glucose across the plasma membranes of mammalian cells. This gene encodes a facilitative glucose transporter that is highly expressed in erythrocytes and endothelial cells, including cells of the blood–brain barrier. The encoded protein is found primarily in the cell membrane and on the cell surface, where it can also function as a receptor for human T-cell leukemia virus (HTLV) I and II. GLUT1 accounts for 2 percent of the protein in the plasma membrane of erythrocytes.
Basigin (BSG) also known as extracellular matrix metalloproteinase inducer (EMMPRIN) or cluster of differentiation 147 (CD147) is a protein that in humans is encoded by the BSG gene. This protein is a determinant for the Ok blood group system. There are three known antigens in the Ok system; the most common being Oka, OK2 and OK3. Basigin has been shown to be an essential receptor on red blood cells for the human malaria parasite, Plasmodium falciparum. The common isoform of basigin (basigin-2) has two immunoglobulin domains, and the extended form basigin-1 has three.
Allan–Herndon–Dudley syndrome is a rare X-linked inherited disorder of brain development that causes both moderate to severe intellectual disability and problems with speech and movement.
ATP-binding cassette transporter sub-family C member 8 is a protein that in humans is encoded by the ABCC8 gene. ABCC8 orthologs have been identified in all mammals for which complete genome data are available.
Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of pyruvate to lactate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from one molecule to another.
Solute carrier family 22 member 1 is a protein that in humans is encoded by the gene SLC22A1.
Monocarboxylate transporter 5 is a protein that in humans is encoded by the SLC16A4 gene.
Monocarboxylate transporter 8 (MCT8) is an active transporter protein that in humans is encoded by the SLC16A2 gene.
Monocarboxylate transporter 4 (MCT4) also known as solute carrier family 16 member 3 is a protein that in humans is encoded by the SLC16A3 gene.
Sodium-coupled monocarboxylate transporter 1 is a protein that in humans is encoded by the SLC5A8 gene.
The monocarboxylate transporters, or MCTs, are a family of proton-linked plasma membrane transporters that carry molecules having one carboxylate group (monocarboxylates), such as lactate, pyruvate, and ketones across biological membranes. MCTs are expressed in nearly every kind of cell.
Monocarboxylate transporter 10, also known as aromatic amino acid transporter 1 and T-type amino acid transporter 1 (TAT1) and solute carrier family 16 member 10 (SLC16A10), is a protein that in humans is encoded by the SLC16A10 gene. SLC16A10 is a member of the solute carrier family.
Monocarboxylate transporter 9 is a protein that in humans is encoded by the SLC16A9 gene.
The lactate shuttle hypothesis describes the movement of lactate intracellularly and intercellularly. The hypothesis is based on the observation that lactate is formed and utilized continuously in diverse cells under both anaerobic and aerobic conditions. Further, lactate produced at sites with high rates of glycolysis and glycogenolysis can be shuttled to adjacent or remote sites including heart or skeletal muscles where the lactate can be used as a gluconeogenic precursor or substrate for oxidation. The hypothesis was proposed by professor George Brooks of the University of California at Berkeley.
Monocarboxylate transporter 2 (MCT2) also known as solute carrier family 16 member 7 (SLC16A7) is a protein that in humans is encoded by the SLC16A7 gene. MCT2 is a proton-coupled monocarboxylate transporter. It catalyzes the rapid transport across the plasma membrane of many monocarboxylates such as lactate, branched-chain oxo acids derived from leucine, valine and isoleucine, and the ketone bodies acetoacetate and beta-hydroxybutyrate. It also functions as high-affinity pyruvate transporter.
Monocarboxylate transporter 3 (MCT3) also known as solute carrier family 16 member 8 is a protein that in humans is encoded by the SLC16A8 gene. MCT is a proton-coupled monocarboxylate transporter. It catalyzes the rapid transport across the plasma membrane of many monocarboxylates such as lactate, pyruvate, branched-chain oxo acids derived from leucine, valine and isoleucine, and the ketone bodies acetoacetate, beta-hydroxybutyrate and acetate. It also functions as high-affinity pyruvate transporter.
The proton-coupled folate transporter is a protein that in humans is encoded by the SLC46A1 gene. The major physiological roles of PCFTs are in mediating the intestinal absorption of folate, and its delivery to the central nervous system.
Proton-coupled amino acid transporters belong to the SLC26A5 family; they are protein receptors whose main function is the transmembrane movement of amino acids and their derivatives. This family of receptors is most commonly found within the luminal surface of the small intestine as well as in some lysosomes. The solute carrier family (SLC) of genes includes roughly 400 membrane proteins that are characterized by 66 families in total. The SLC36 family of genes maps to chromosome 11. The diversity of these receptors is vast, with the ability to transport both charged and uncharged amino acids along with their derivatives. In research and practice, SLC36A1/2 are both targets for drug-based delivery systems for a wide range of disorders.
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