Intracellular and Extracellular Carbonic Anhydrases Cooperate Non-enzymatically to Enhance Activity of Monocarboxylate Transporters

Klier, Michael; Andes, Fabian T.; Deitmer, Joachim W.; Becker, Holger M.

doi:10.1074/jbc.m113.537043

Cited by 56 publications

(65 citation statements)

References 52 publications

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“…For a more comprehensive review on bicarbonate transport metabolons see Refs. 39 -41. Using heterologous protein expression in Xenopus oocytes, we have recently reported that CAII enhances transport activity of MCT1 and MCT4, while leaving transport activity of MCT2 unaffected (42)(43)(44)(45)(46). In contrast to the transport metabolons described so far, this interaction is independent of CAII catalytic activity but is mediated by an intramolecular H ϩ shuttle within the enzyme (47,48).…”

mentioning

confidence: 63%

“…We have previously shown that CAII facilitates transport activity of MCT1, but not MCT2, when the proteins are heterologously expressed in Xenopus oocytes (42,43,(45)(46)(47)(48)(49). Facilitation of MCT1 transport function has been found to be independent of the catalytic activity of the enzyme (42, 43) but required both the intramolecular H ϩ shuttle of CAII (CAIIHis 64 ) (48) and the CAII-binding site 489 EEE in the C terminus of MCT1 (49).…”

Section: Discussionmentioning

confidence: 99%

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Analysis of the Binding Moiety Mediating the Interaction between Monocarboxylate Transporters and Carbonic Anhydrase II

Noor¹,

Dietz²,

Heidtmann

et al. 2015

Journal of Biological Chemistry

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Background: Carbonic anhydrase II (CAII) augments activity of monocarboxylate transporters (MCTs) by noncatalytic interaction. Results: CAII binds to an acidic cluster with an appropriate context in the MCT C terminus. Conclusion: Isoform-specific interaction between MCTs and CAII requires a specific binding moiety. Significance: CAII-mediated increase in lactate transport depends on the presence of a specific binding moiety in MCT.Proton-coupled monocarboxylate transporters (MCTs) mediate the exchange of high energy metabolites like lactate between different cells and tissues. We have reported previously that carbonic anhydrase II augments transport activity of MCT1 and MCT4 by a noncatalytic mechanism, while leaving transport activity of MCT2 unaltered. In the present study, we combined electrophysiological measurements in Xenopus oocytes and pulldown experiments to analyze the direct interaction between carbonic anhydrase II (CAII) and MCT1, MCT2, and MCT4, respectively. Transport activity of MCT2-WT, which lacks a putative CAII-binding site, is not augmented by CAII. However, introduction of a CAII-binding site into the C terminus of MCT2 resulted in CAII-mediated facilitation of MCT2 transport activity. Interestingly, introduction of three glutamic acid residues alone was not sufficient to establish a direct interaction between MCT2 and CAII, but the cluster had to be arranged in a fashion that allowed access to the binding moiety in CAII. We further demonstrate that functional interaction between MCT4 and CAII requires direct binding of the enzyme to the acidic cluster 431 EEE in the C terminus of MCT4 in a similar fashion as previously shown for binding of CAII to the cluster 489 EEE in the C terminus of MCT1. In CAII, binding to MCT1 and MCT4 is mediated by a histidine residue at position 64. Taken together, our results suggest that facilitation of MCT transport activity by CAII requires direct binding between histidine 64 in CAII and a cluster of glutamic acid residues in the C terminus of the transporter that has to be positioned in surroundings that allow access to CAII.

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confidence: 63%

Section: Discussionmentioning

confidence: 99%

Analysis of the Binding Moiety Mediating the Interaction between Monocarboxylate Transporters and Carbonic Anhydrase II

Noor¹,

Dietz²,

Heidtmann

et al. 2015

Journal of Biological Chemistry

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“…CA is known to inhibit MCT4, preventing monocarboxylate uptake and therefore inhibiting extracellular lactate transport (24). In addition, IS may block lactate transport via inhibition of CA9 activity (4).…”

Section: Discussionmentioning

confidence: 99%

Combination of lactate calcium salt with 5-indanesulfonamide and α-cyano-4-hydroxycinnamic acid to enhance the antitumor effect on HCT116 cells via intracellular acidification

et al. 2016

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Abstract. Maintenance of a neutral intracellular pH (pHi) is favorable for the survival of tumors, and maintenance of highly acidic extracellular pH (pHe) facilitates tumor invasiveness. The aim of the present study was to investigate the antitumor effects of lactate calcium salt (CaLa), 5-indanesulfonamide (IS) and α-cyano-4-hydroxycinnamic acid (CA) via pH regulation in colon cancer cells. HCT116 cells were treated with CaLa, IS, CA and combinations of the three. Subsequently, the concentration of intracellular lactate was determined. pHi and pHe were measured using cell lysates and culture media. Colony formation assay, cell viability assay and western blot analysis were additionally performed to analyze the consequences of the pH changes. CaLa, IS, CA and combination treatments induced an increase in the concentration of intracellular lactate. Lactate influx into the tumor microenvironment produced an acidic pHi in colon cancer cells. Consequently, colony formation and cell viability were significantly decreased, as well as poly(adenosine diphosphate-ribose) polymerase degradation. The tumor microenvironment may be exploited therapeutically by disrupting the mechanism that regulates pHi, leading to cell apoptosis. The present study indicated that treatment with CaLa, IS and CA induced intracellular acidification via lactate influx, causing apoptosis of colon cancer cells.Additionally, the findings suggested that the combination of CaLa with IS and CA may enhance antitumor activity, and may provide a potential therapeutic approach for the treatment of colon cancer.

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“…The rate of production can increase 50-fold if either glucose or glycogen is required to generate ATP in the absence of oxygen [57]. Lactate is transported out of the cell via monocarboxylate transporters (MCT) in an electroneutral transport mode of 1 H + : 1 Lactate [58]. H + transport system under conditions of exclusively aerobic metabolism is used by the cell to maintain a facilitation of CO 2 diffusion, whereas under conditions of dominating anaerobic glycolysis and low intracellular pH, it is mainly used to transport H + along with the lactate anion through the monocarboxylate transporters (MCT), a prerequisite for the elimination of lactic acid from the cell.…”

Section: Discussionmentioning

confidence: 99%

Carbonic Anhydrase: A New Therapeutic Target for Managing Diabetes

Ismail¹,

Amodu²

2016

J Metabolic Synd

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Intracellular and Extracellular Carbonic Anhydrases Cooperate Non-enzymatically to Enhance Activity of Monocarboxylate Transporters

Cited by 56 publications

References 52 publications

Analysis of the Binding Moiety Mediating the Interaction between Monocarboxylate Transporters and Carbonic Anhydrase II

Analysis of the Binding Moiety Mediating the Interaction between Monocarboxylate Transporters and Carbonic Anhydrase II

Combination of lactate calcium salt with 5-indanesulfonamide and α-cyano-4-hydroxycinnamic acid to enhance the antitumor effect on HCT116 cells via intracellular acidification

Carbonic Anhydrase: A New Therapeutic Target for Managing Diabetes

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