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Functions of Enyolreductase ( ER) Domains of PKS Cluster in Lipid Synthesis and Enhancement of PUFAs Accumulation in Schizochytrium limacinum SR21 Using Triclosan as a Regulator of ER. Microorganisms 2020; 8:microorganisms8020300. [PMID: 32098234 PMCID: PMC7074904 DOI: 10.3390/microorganisms8020300] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/09/2020] [Accepted: 02/19/2020] [Indexed: 01/10/2023] Open
Abstract
The polyketide synthase (PKS) cluster genes are supposed to synthesize polyunsaturated fatty acids (PUFAs) in S. limacinum. In this study, two enyolreductase (ER) genes located on PKS cluster were knocked out through homologous recombination to explore their functions. The knock-out of OrfB-ER (located on OrfB subunit) decreased lipid content and had obvious decrease on PUFAs content, indicating OrfB-ER domain played a vital role on PUFAs synthesis; the knock-out of OrfC-ER (located on OrfC subunit) decreased SFAs content and increased total lipid content, indicating OrfC-ER domain was likely to be related with SFAs synthesis, and lipid production could be improved by down-regulating OrfC-ER domain expression. Therefore, the addition of triclosan as a reported regulator of ER domain induced the increase of PUFAs production by 51.74% and lipids yield by 47.63%. Metabolic analysis indicated triclosan played its role through inhibiting the expression of OrfC-ER to reduce the feedback inhibition of SFAs and further to enhance NADPH synthesis for lipid production, and by weakening mevalonate pathway and tricarboxylic acid (TCA) cycle to shift precursors for lipid and PUFAs synthesis. This research illuminates functions of two ER domains in S. limacinum and provides a potential targets for improving lipid production.
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2
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Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
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Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
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3
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Structural basis for regulation of human acetyl-CoA carboxylase. Nature 2018; 558:470-474. [DOI: 10.1038/s41586-018-0201-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 04/24/2018] [Indexed: 11/08/2022]
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4
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Arlia-Ciommo A, Svistkova V, Mohtashami S, Titorenko VI. A novel approach to the discovery of anti-tumor pharmaceuticals: searching for activators of liponecrosis. Oncotarget 2017; 7:5204-25. [PMID: 26636650 PMCID: PMC4868681 DOI: 10.18632/oncotarget.6440] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/21/2015] [Indexed: 02/04/2023] Open
Abstract
A recently conducted chemical genetic screen for pharmaceuticals that can extend longevity of the yeast Saccharomyces cerevisiae has identified lithocholic acid as a potent anti-aging molecule. It was found that this hydrophobic bile acid is also a selective anti-tumor chemical compound; it kills different types of cultured cancer cells if used at concentrations that do not compromise the viability of non-cancerous cells. These studies have revealed that yeast can be successfully used as a model organism for high-throughput screens aimed at the discovery of selectively acting anti-tumor small molecules. Two metabolic traits of rapidly proliferating fermenting yeast, namely aerobic glycolysis and lipogenesis, are known to be similar to those of cancer cells. The mechanisms underlying these key metabolic features of cancer cells and fermenting yeast have been established; such mechanisms are discussed in this review. We also suggest how a yeast-based chemical genetic screen can be used for the high-throughput development of selective anti-tumor pharmaceuticals that kill only cancer cells. This screen consists of searching for chemical compounds capable of increasing the abundance of membrane lipids enriched in unsaturated fatty acids that would therefore be toxic only to rapidly proliferating cells, such as cancer cells and fermenting yeast.
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Affiliation(s)
| | | | - Sadaf Mohtashami
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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5
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Schuchmann K, Vonck J, Müller V. A bacterial hydrogen-dependent CO2 reductase forms filamentous structures. FEBS J 2016; 283:1311-22. [PMID: 26833643 DOI: 10.1111/febs.13670] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/16/2016] [Accepted: 01/25/2016] [Indexed: 12/01/2022]
Abstract
Interconversion of CO2 and formic acid is an important reaction in bacteria. A novel enzyme complex that directly utilizes molecular hydrogen as electron donor for the reversible reduction of CO2 has recently been identified in the Wood-Ljungdahl pathway of an acetogenic bacterium. This pathway is utilized for carbon fixation as well as energy conservation. Here we describe the further characterization of the quaternary structure of this enzyme complex and the unexpected behavior of this enzyme in polymerizing into filamentous structures. Polymerization of metabolic enzymes into similar structures has been observed only in rare cases but the increasing number of examples point towards a more general characteristic of enzyme functioning. Polymerization of the purified enzyme into ordered filaments of more than 0.1 μm in length was only dependent on the presence of divalent cations. Polymerization was a reversible process and connected to the enzymatic activity of the oxygen-sensitive enzyme with the filamentous form being the most active state.
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Affiliation(s)
- Kai Schuchmann
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
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6
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Engineering lipid overproduction in the oleaginous yeast Yarrowia lipolytica. Metab Eng 2015; 29:56-65. [DOI: 10.1016/j.ymben.2015.02.005] [Citation(s) in RCA: 241] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 02/16/2015] [Indexed: 12/20/2022]
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7
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Barry RM, Gitai Z. Self-assembling enzymes and the origins of the cytoskeleton. Curr Opin Microbiol 2011; 14:704-11. [PMID: 22014508 DOI: 10.1016/j.mib.2011.09.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 09/23/2011] [Accepted: 09/29/2011] [Indexed: 12/22/2022]
Abstract
The bacterial cytoskeleton is composed of a complex and diverse group of proteins that self-assemble into linear filaments. These filaments support and organize cellular architecture and provide a dynamic network controlling transport and localization within the cell. Here, we review recent discoveries related to a newly appreciated class of self-assembling proteins that expand our view of the bacterial cytoskeleton and provide potential explanations for its evolutionary origins. Specifically, several types of metabolic enzymes can form structures similar to established cytoskeletal filaments and, in some cases, these structures have been repurposed for structural uses independent of their normal roles. The behaviors of these enzymes suggest that some modern cytoskeletal proteins may have evolved from dual-role proteins with catalytic and structural functions.
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Affiliation(s)
- Rachael M Barry
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States
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8
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Roles of StearoylCoA Desaturase-1 in the Regulation of Cancer Cell Growth, Survival and Tumorigenesis. Cancers (Basel) 2011; 3:2462-77. [PMID: 24212819 PMCID: PMC3757427 DOI: 10.3390/cancers3022462] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 04/27/2011] [Accepted: 05/11/2011] [Indexed: 12/24/2022] Open
Abstract
The development and maintenance of defining features of cancer, such as unremitting cell proliferation, evasion of programmed cell death, and the capacity for colonizing local tissues and distant organs, demand a massive production of structural, signaling and energy-storing lipid biomolecules of appropriate fatty acid composition. Due to constitutive activation of fatty acid biosynthesis, cancer cell lipids are enriched with saturated (SFA) and, in particular, monounsaturated fatty acids (MUFA), which are generated by StearoylCoA desaturase-1, the main enzyme that transforms SFA into MUFA. An increasing number of experimental and epidemiological studies suggest that high levels of SCD1 activity is a major factor in establishing the biochemical and metabolic perturbations that favors the oncogenic process. This review examines evidence that suggests the critical implication of SCD1 in the modulation of multiple biological mechanisms, specifically lipid biosynthesis and proliferation and survival signaling pathways that contribute to the development and progression of cancer.
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9
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Vigueira PA, Paul KS. Requirement for acetyl-CoA carboxylase in Trypanosoma brucei is dependent upon the growth environment. Mol Microbiol 2011; 80:117-32. [PMID: 21306439 DOI: 10.1111/j.1365-2958.2011.07563.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Trypanosoma brucei, the causative agent of human African trypanosomiasis, possesses two fatty acid synthesis pathways: a major de novo synthesis pathway in the ER and a mitochondrial pathway. The 2-carbon donor for both pathways is malonyl-CoA, which is synthesized from acetyl-CoA by Acetyl-CoA carboxylase (ACC). Here, we show that T. brucei ACC shares the same enzyme architecture and moderate ∼ 30% identity with yeast and human ACCs. ACC is cytoplasmic and appears to be distributed throughout the cell in numerous puncta distinct from glycosomes and other organelles. ACC is active in both bloodstream and procyclic forms. Reduction of ACC activity by RNA interference (RNAi) resulted in a stage-specific phenotype. In procyclic forms, ACC RNAi resulted in 50-75% reduction in fatty acid elongation and a 64% reduction in growth in low-lipid media. In bloodstream forms, ACC RNAi resulted in a minor 15% decrease in fatty acid elongation and no growth defect in culture, even in low-lipid media. However, ACC RNAi did attenuate virulence in a mouse model of infection. Thus the requirement for ACC in T. brucei is dependent upon the growth environment in two different life cycle stages.
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Affiliation(s)
- Patrick A Vigueira
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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10
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Igal RA. Stearoyl-CoA desaturase-1: a novel key player in the mechanisms of cell proliferation, programmed cell death and transformation to cancer. Carcinogenesis 2010; 31:1509-15. [PMID: 20595235 DOI: 10.1093/carcin/bgq131] [Citation(s) in RCA: 227] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
As part of a shift toward macromolecule production to support continuous cell proliferation, cancer cells coordinate the activation of lipid biosynthesis and the signaling networks that stimulate this process. A ubiquitous metabolic event in cancer is the constitutive activation of the fatty acid biosynthetic pathway, which produces saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) to sustain the increasing demand of new membrane phospholipids with appropriate acyl composition. In cancer cells, the tandem activation of the fatty acid biosynthetic enzymes adenosine triphosphate citrate lyase, acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) leads to increased synthesis of SFA and their further conversion into MUFA by stearoyl-CoA desaturase (SCD) 1. The roles of adenosine triphosphate citrate lyase, ACC and FAS in the pathogenesis of cancer have been a subject of extensive investigation. However, despite early experimental and epidemiological observations reporting elevated levels of MUFA in cancer cells and tissues, the involvement of SCD1 in the mechanisms of carcinogenesis remains surprisingly understudied. Over the past few years, a more detailed picture of the functional relevance of SCD1 in cell proliferation, survival and transformation to cancer has begun to emerge. The present review addresses the mounting evidence that argues for a key role of SCD1 in the coordination of the intertwined pathways of lipid biosynthesis, energy sensing and the transduction signals that influence mitogenesis and tumorigenesis, as well as the potential value of this enzyme as a target for novel pharmacological approaches in cancer interventions.
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Affiliation(s)
- R Ariel Igal
- Department of Nutritional Sciences and Rutgers Center for Lipid Research, Rutgers, the State University of New Jersey, 96 Lipman Drive, New Brunswick, NJ 08901-8525, USA.
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11
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Scaglia N, Chisholm JW, Igal RA. Inhibition of stearoylCoA desaturase-1 inactivates acetyl-CoA carboxylase and impairs proliferation in cancer cells: role of AMPK. PLoS One 2009; 4:e6812. [PMID: 19710915 PMCID: PMC2728543 DOI: 10.1371/journal.pone.0006812] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 08/04/2009] [Indexed: 01/22/2023] Open
Abstract
Cancer cells activate the biosynthesis of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in order to sustain an increasing demand for phospholipids with appropriate acyl composition during cell replication. We have previously shown that a stable knockdown of stearoyl-CoA desaturase 1 (SCD1), the main Δ9-desaturase that converts SFA into MUFA, in cancer cells decreases the rate of lipogenesis, reduces proliferation and in vitro invasiveness, and dramatically impairs tumor formation and growth. Here we report that pharmacological inhibition of SCD1 with a novel small molecule in cancer cells promoted the activation of AMP-activated kinase (AMPK) and the subsequent reduction of acetylCoA carboxylase activity, with a concomitant inhibition of glucose-mediated lipogenesis. The pharmacological inhibition of AMPK further decreased proliferation of SCD1-depleted cells, whereas AMPK activation restored proliferation to control levels. Addition of supraphysiological concentrations of glucose or pyruvate, the end product of glycolysis, did not reverse the low proliferation rate of SCD1-ablated cancer cells. Our data suggest that cancer cells require active SCD1 to control the rate of glucose-mediated lipogenesis, and that when SCD1 activity is impaired cells downregulate SFA synthesis via AMPK-mediated inactivation of acetyl-CoA carboxylase, thus preventing the harmful effects of SFA accumulation.
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Affiliation(s)
- Natalia Scaglia
- Department of Nutritional Sciences and Rutgers Center for Lipid Research, Rutgers, the State University of New Jersey, New Brunswick, New Jersey, United States of America
| | - Jeffrey W. Chisholm
- Biology, Gilead Sciences, Inc., Palo Alto, California, United States of America
| | - R. Ariel Igal
- Department of Nutritional Sciences and Rutgers Center for Lipid Research, Rutgers, the State University of New Jersey, New Brunswick, New Jersey, United States of America
- * E-mail:
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12
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Barber MC, Price NT, Travers MT. Structure and regulation of acetyl-CoA carboxylase genes of metazoa. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:1-28. [PMID: 15749055 DOI: 10.1016/j.bbalip.2004.12.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 11/02/2004] [Accepted: 12/01/2004] [Indexed: 11/16/2022]
Abstract
Acetyl-CoA carboxylase (ACC) plays a fundamental role in fatty acid metabolism. The reaction product, malonyl-CoA, is both an intermediate in the de novo synthesis of long-chain fatty acids and also a substrate for distinct fatty acyl-CoA elongation enzymes. In metazoans, which have evolved energy storage tissues to fuel locomotion and to survive periods of starvation, energy charge sensing at the level of the individual cell plays a role in fuel selection and metabolic orchestration between tissues. In mammals, and probably other metazoans, ACC forms a component of an energy sensor with malonyl-CoA, acting as a signal to reciprocally control the mitochondrial transport step of long-chain fatty acid oxidation through the inhibition of carnitine palmitoyltransferase I (CPT I). To reflect this pivotal role in cell function, ACC is subject to complex regulation. Higher metazoan evolution is associated with the duplication of an ancestral ACC gene, and with organismal complexity, there is an increasing diversity of transcripts from the ACC paraloges with the potential for the existence of several isozymes. This review focuses on the structure of ACC genes and the putative individual roles of their gene products in fatty acid metabolism, taking an evolutionary viewpoint provided by data in genome databases.
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Affiliation(s)
- Michael C Barber
- Hannah Research Institute, Ayr, KA6 5HL, Scotland, United Kingdom.
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13
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Munday MR, Hemingway CJ. The regulation of acetyl-CoA carboxylase--a potential target for the action of hypolipidemic agents. ADVANCES IN ENZYME REGULATION 1999; 39:205-34. [PMID: 10470374 DOI: 10.1016/s0065-2571(98)00016-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ACC exists as two major isoforms ACC1 or ACC alpha, and ACC2 or ACC beta, and there is evidence that they play separate roles in the production of malonyl-CoA for fatty acid synthesis and the control of mitochondrial beta-oxidation, respectively. ACC alpha can be regulated at the level of gene expression, allosteric regulation of the enzyme, and reversible phosphorylation by AMP-PK. Emerging lines of research suggest that similar mechanisms of regulation exist for ACC beta. Its inactivation in heart and skeletal muscle through phosphorylation by AMP-PK is becoming well-established. ACC is an important target of certain hypolipidemic drugs such as the fibrates. This is not simply because ACC alpha inhibition decreases the synthesis of a lipid component of VLDL because fatty acids synthesized de novo in liver are not always major contributors to VLDL lipid (158); it is also because ACC beta inhibition leads to a decrease in malonyl-CoA levels and the disinhibition of fatty acid oxidation. Partitioning fatty acids towards oxidation and away from esterification is an important aspect of the lipid-lowering effects of fibrates. Fibrates could use any of the mechanisms of ACC regulation to decrease activity. They could repress ACC gene expression through the activation of PPAR alpha, and fibroyl-CoA esters could inhibit ACC allosterically just as TOFyl-CoA does. However, we have demonstrated a rapid inactivation of ACC in cultured rat hepatocytes by gemfibrozil that is mediated by activation of AMP-PK and the subsequent phosphorylation of ACC. The end result is the inhibition of hepatic fatty acid synthesis and a possible activation of beta-oxidation as evidenced by the increased production of ketone bodies. The mechanism through which fibrates activate the AMP-PK cascade, the role of PPAR alpha, the physiological responses of biosynthesis and oxidation and the use of these mechanisms by other hypolipidemic agents are areas of ongoing investigation.
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Affiliation(s)
- M R Munday
- Department of Pharmaceutical and Biological Chemistry, School of Pharmacy, University of London, UK
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Hillgartner FB, Charron T. Arachidonate and medium-chain fatty acids inhibit transcription of the acetyl-CoA carboxylase gene in hepatocytes in culture. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)30039-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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15
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Abstract
Most enzymes exist as oligomers or polymers, and a significant subset of these (perhaps 15% of all enzymes) can reversibly dissociate and reassociate in response to an effector ligand. Such a change in subunit assembly usually is accompanied by a change in enzyme activity, providing a mechanism for regulation. Two models are described for a physical mechanism, leading to a change in activity: (1) catalytic activity depends on subunit conformation, which is modulated by subunit dissociation; and (2) catalytic or regulatory sites are located at subunit interfaces and are disrupted by subunit dissociation. Examples of such enzymes show that both catalytic sites and regulatory sites occur at the junction of 2 subunits. In addition, for 9 enzymes, kinetic studies supported the existence of a separate regulatory site with significantly different affinity for the binding of either a substrate or a product of that enzyme. Over 40 dissociating enzymes are described from 3 major metabolic areas: carbohydrate metabolism, nucleotide metabolism, and amino acid metabolism. Important variables that influence enzyme dissociation include: enzyme concentration, ligand concentration, other cellular proteins, pH, and temperature. All these variables can be readily manipulated in vitro, but normally only the first two are physiological variables. Seven of these enzymes are most active as the dissociated monomer, the others as oligomers, emphasizing the importance of a regulated equilibrium between 2 or more conformational states. Experiments to test whether enzyme dissociation occurs in vivo showed this to be the case in 6 out of 7 studies, with 4 different enzymes.
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Affiliation(s)
- T W Traut
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599-7260
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Rose-Kahn G, Bar-Tana J. Inhibition of rat liver acetyl-CoA carboxylase by beta, beta'-tetramethyl-substituted hexadecanedioic acid (MEDICA 16). BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1042:259-64. [PMID: 1967952 DOI: 10.1016/0005-2760(90)90018-s] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Rat liver acetyl-CoA carboxylase activity was inhibited by the free as well as the CoA monothioester of beta, beta'-methyl-substituted hexadecanedioic acid (MEDICA 16) (Bar-Tana, J., Rose-Kahn, G. and Srebnik, M. (1985) J. Biol. Chem. 260, 8404-8410 (1985). (1) The CoA monothioester of MEDICA 16 served as a dead-end inhibitor with an apparent Ki of 2 microM and 58 microM for the biotin-carboxylated and noncarboxylated enzyme forms, respectively. MEDICA 16-CoA binding was not mutually exclusive with that of citrate and did not affect the avidin-resistance of rat liver acetyl-CoA carboxylase. (2) The free dioic acid of MEDICA 16 was competitive to citrate, having an apparent Ki of about 70 microM, as compared to a Ka of 2-8 mM for the citrate activator. Inhibition of the carboxylase by the free dioic acid of MEDICA 16 was accompanied by an increase in its avidin resistance. The resultant inhibition of acetyl-CoA carboxylase by MEDICA 16 and its CoA thioester, together with the previously reported citrate-competitive inhibition of ATP-citrate lyase by MEDICA 16, may account for the observed hypolipidemic effect of MEDICA 16 under dietary conditions where liver lipogenesis constitutes a major flux of liver lipid synthesis.
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Affiliation(s)
- G Rose-Kahn
- Department of Biochemistry, Hebrew University, Hadassah Medical School, Jerusalem, Israel
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Affiliation(s)
- D G Hardie
- Biochemistry Department, University, Dundee, Scotland, U.K
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18
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Jamil H, Madsen NB. Phosphorylation state of acetyl-coenzyme A carboxylase. II. Variation with nutritional condition. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(19)75831-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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19
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Clarke SD. Rapid changes in chick liver acetyl-CoA carboxylase indicative of phosphorylation control. Biochem Biophys Res Commun 1983; 116:633-8. [PMID: 6140006 DOI: 10.1016/0006-291x(83)90571-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Liver fatty acid synthesis was suppressed 75,95 and 90% within 1, 2 and 4 hrs respectively of depriving chicks of food. Accompanying this rapid drop in lipogenesis was a marked reduction in acetyl-CoA carboxylase activity, i.e., 40 and 75% decrease after 2 and 4 hrs of fasting. Adding 10 mM citrate to the crude liver supernatant, or incubating the supernatant at 37 degrees, 30 min increased activity of the briefly fasted birds, but neither method restored carboxylase activity to fed level. Heat and citrate activation were additive and together resulted in an activity comparable to the fed condition. The heat-dependent activation was accelerated by exogenous phosphoprotein phosphatase, and completely blocked by 100 mM NaF. Thus, enhancement of carboxylase activity from liver of briefly fasted chicks appears to be a dephosphorylation process. This is the first report indicating acute changes in chick carboxylase activity may involve a phosphorylation-dephosphorylation mechanism.
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21
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22
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Herzberg GR. The influence of dietary fatty acid composition on lipogenesis. ADVANCES IN NUTRITIONAL RESEARCH 1983; 5:221-53. [PMID: 6133419 DOI: 10.1007/978-1-4613-9937-7_10] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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23
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Clarke BA, Clarke SD. Polymer-protomer transition of acetyl-CoA carboxylase as a regulator of lipogenesis in rat liver. Arch Biochem Biophys 1982; 218:92-100. [PMID: 6128959 DOI: 10.1016/0003-9861(82)90324-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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24
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Schwartz RS, Abraham S. Effect of dietary polyunsaturated fatty acids on the activity and content of fatty acid synthetase in mouse liver. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 711:316-26. [PMID: 7093300 DOI: 10.1016/0005-2760(82)90041-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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