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Nancolas B, Bull ID, Stenner R, Dufour V, Curnow P. Saccharomyces cerevisiae Atf1p is an alcohol acetyltransferase and a thioesterase in vitro. Yeast 2017; 34:239-251. [PMID: 28160314 PMCID: PMC5484351 DOI: 10.1002/yea.3229] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 01/30/2017] [Accepted: 02/01/2017] [Indexed: 11/09/2022] Open
Abstract
The alcohol-O-acyltransferases are bisubstrate enzymes that catalyse the transfer of acyl chains from an acyl-coenzyme A (CoA) donor to an acceptor alcohol. In the industrial yeast Saccharomyces cerevisiae this reaction produces acyl esters that are an important influence on the flavour of fermented beverages and foods. There is also a growing interest in using acyltransferases to produce bulk quantities of acyl esters in engineered microbial cell factories. However, the structure and function of the alcohol-O-acyltransferases remain only partly understood. Here, we recombinantly express, purify and characterize Atf1p, the major alcohol acetyltransferase from S. cerevisiae. We find that Atf1p is promiscuous with regard to the alcohol cosubstrate but that the acyltransfer activity is specific for acetyl-CoA. Additionally, we find that Atf1p is an efficient thioesterase in vitro with specificity towards medium-chain-length acyl-CoAs. Unexpectedly, we also find that mutating the supposed catalytic histidine (H191) within the conserved HXXXDG active site motif only moderately reduces the thioesterase activity of Atf1p. Our results imply a role for Atf1p in CoA homeostasis and suggest that engineering Atf1p to reduce the thioesterase activity could improve product yields of acetate esters from cellular factories. © 2017 The Authors. Yeast published by John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Ian D Bull
- School of Chemistry, University of Bristol, Bristol, UK
| | - Richard Stenner
- School of Biochemistry, University of Bristol, Bristol, UK.,Bristol Centre for Functional Nanomaterials, University of Bristol, Bristol, UK
| | - Virginie Dufour
- School of Biochemistry, University of Bristol, Bristol, UK.,BrisSynBio, Life Sciences Building, Tyndall Avenue, Bristol, UK
| | - Paul Curnow
- School of Biochemistry, University of Bristol, Bristol, UK.,BrisSynBio, Life Sciences Building, Tyndall Avenue, Bristol, UK
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Nath K, Guo L, Nancolas B, Nelson DS, Shestov AA, Lee SC, Roman J, Zhou R, Leeper DB, Halestrap AP, Blair IA, Glickson JD. Mechanism of antineoplastic activity of lonidamine. Biochim Biophys Acta Rev Cancer 2016; 1866:151-162. [PMID: 27497601 DOI: 10.1016/j.bbcan.2016.08.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/26/2016] [Accepted: 08/03/2016] [Indexed: 12/19/2022]
Abstract
Lonidamine (LND) was initially introduced as an antispermatogenic agent. It was later found to have anticancer activity sensitizing tumors to chemo-, radio-, and photodynamic-therapy and hyperthermia. Although the mechanism of action remained unclear, LND treatment has been known to target metabolic pathways in cancer cells. It has been reported to alter the bioenergetics of tumor cells by inhibiting glycolysis and mitochondrial respiration, while indirect evidence suggested that it also inhibited l-lactic acid efflux from cells mediated by members of the proton-linked monocarboxylate transporter (MCT) family and also pyruvate uptake into the mitochondria by the mitochondrial pyruvate carrier (MPC). Recent studies have demonstrated that LND potently inhibits MPC activity in isolated rat liver mitochondria (Ki 2.5μM) and cooperatively inhibits l-lactate transport by MCT1, MCT2 and MCT4 expressed in Xenopus laevis oocytes with K0.5 and Hill coefficient values of 36-40μM and 1.65-1.85, respectively. In rat heart mitochondria LND inhibited the MPC with similar potency and uncoupled oxidation of pyruvate was inhibited more effectively (IC50~7μM) than other substrates including glutamate (IC50~20μM). LND inhibits the succinate-ubiquinone reductase activity of respiratory Complex II without fully blocking succinate dehydrogenase activity. LND also induces cellular reactive oxygen species through Complex II and has been reported to promote cell death by suppression of the pentose phosphate pathway, which resulted in inhibition of NADPH and glutathione generation. We conclude that MPC inhibition is the most sensitive anti-tumour target for LND, with additional inhibitory effects on MCT-mediated l-lactic acid efflux, Complex II and glutamine/glutamate oxidation.
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Affiliation(s)
- Kavindra Nath
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - Lili Guo
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Bethany Nancolas
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, BS8 1TD, UK
| | - David S Nelson
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Alexander A Shestov
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Seung-Cheol Lee
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeffrey Roman
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Rong Zhou
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Dennis B Leeper
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Andrew P Halestrap
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, BS8 1TD, UK
| | - Ian A Blair
- Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jerry D Glickson
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
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Knight MJ, Senior L, Nancolas B, Ratcliffe S, Curnow P. Direct evidence of the molecular basis for biological silicon transport. Nat Commun 2016; 7:11926. [PMID: 27305972 PMCID: PMC4912633 DOI: 10.1038/ncomms11926] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 05/11/2016] [Indexed: 12/19/2022] Open
Abstract
Diatoms are an important group of eukaryotic algae with a curious evolutionary innovation: they sheath themselves in a cell wall made largely of silica. The cellular machinery responsible for silicification includes a family of membrane permeases that recognize and actively transport the soluble precursor of biosilica, silicic acid. However, the molecular basis of silicic acid transport remains obscure. Here, we identify experimentally tractable diatom silicic acid transporter (SIT) homologues and study their structure and function in vitro, enabled by the development of a new fluorescence method for studying substrate transport kinetics. We show that recombinant SITs are Na+/silicic acid symporters with a 1:1 protein: substrate stoichiometry and KM for silicic acid of 20 μM. Protein mutagenesis supports the long-standing hypothesis that four conserved GXQ amino acid motifs are important in SIT function. This marks a step towards a detailed understanding of silicon transport with implications for biogeochemistry and bioinspired materials. Diatoms sheath themselves in a self-made casing of silica, which requires the function of silicic acid transporters. Here, the authors identify versions of these transporters that are experimentally tractable, and develop a fluorescence method to study silicic acid transport in vitro.
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Affiliation(s)
- Michael J Knight
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Laura Senior
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Bethany Nancolas
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Sarah Ratcliffe
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Paul Curnow
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK.,BrisSynBio, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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Nancolas B, Guo L, Zhou R, Nath K, Nelson DS, Leeper DB, Blair IA, Glickson JD, Halestrap AP. The anti-tumour agent lonidamine is a potent inhibitor of the mitochondrial pyruvate carrier and plasma membrane monocarboxylate transporters. Biochem J 2016; 473:929-36. [PMID: 26831515 PMCID: PMC4814305 DOI: 10.1042/bj20151120] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/01/2016] [Indexed: 12/25/2022]
Abstract
Lonidamine (LND) is an anti-tumour drug particularly effective at selectively sensitizing tumours to chemotherapy, hyperthermia and radiotherapy, although its precise mode of action remains unclear. It has been reported to perturb the bioenergetics of cells by inhibiting glycolysis and mitochondrial respiration, whereas indirect evidence suggests it may also inhibit L-lactic acid efflux from cells mediated by members of the proton-linked monocarboxylate transporter (MCT) family and also pyruvate uptake into the mitochondria by the mitochondrial pyruvate carrier (MPC). In the present study, we test these possibilities directly. We demonstrate that LND potently inhibits MPC activity in isolated rat liver mitochondria (Ki2.5 μM) and co-operatively inhibits L-lactate transport by MCT1, MCT2 and MCT4 expressed in Xenopus laevisoocytes with K0.5 and Hill coefficient values of 36-40 μM and 1.65-1.85 respectively. In rat heart mitochondria LND inhibited the MPC with similar potency and uncoupled oxidation of pyruvate was inhibited more effectively (IC50~ 7 μM) than other substrates including glutamate (IC50~ 20 μM). In isolated DB-1 melanoma cells 1-10 μM LND increased L-lactate output, consistent with MPC inhibition, but higher concentrations (150 μM) decreased L-lactate output whereas increasing intracellular [L-lactate] > 5-fold, consistent with MCT inhibition. We conclude that MPC inhibition is the most sensitive anti-tumour target for LND, with additional inhibitory effects on MCT-mediated L-lactic acid efflux and glutamine/glutamate oxidation. Together these actions can account for published data on the selective tumour effects of LND onL-lactate, intracellular pH (pHi) and ATP levels that can be partially mimicked by the established MPC and MCT inhibitor α-cyano-4-hydroxycinnamate (CHC).
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Affiliation(s)
- Bethany Nancolas
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, U.K
| | - Lili Guo
- Penn Superfund Research and Training Program Center, Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, U.S.A
| | - Rong Zhou
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania School of Medicine, B6 Blockley Hall, Philadelphia, PA 19104, U.S.A
| | - Kavindra Nath
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania School of Medicine, B6 Blockley Hall, Philadelphia, PA 19104, U.S.A
| | - David S Nelson
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania School of Medicine, B6 Blockley Hall, Philadelphia, PA 19104, U.S.A
| | - Dennis B Leeper
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA 19107, U.S.A
| | - Ian A Blair
- Penn Superfund Research and Training Program Center, Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, U.S.A
| | - Jerry D Glickson
- Laboratory of Molecular Imaging, Department of Radiology, University of Pennsylvania School of Medicine, B6 Blockley Hall, Philadelphia, PA 19104, U.S.A
| | - Andrew P Halestrap
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, U.K.
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