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Moon JS, Hisata S, Park MA, DeNicola GM, Ryter SW, Nakahira K, Choi AMK. mTORC1-Induced HK1-Dependent Glycolysis Regulates NLRP3 Inflammasome Activation. Cell Rep 2015; 12:102-115. [PMID: 26119735 PMCID: PMC4858438 DOI: 10.1016/j.celrep.2015.05.046] [Citation(s) in RCA: 307] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 03/24/2015] [Accepted: 05/22/2015] [Indexed: 12/20/2022] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) regulates activation of immune cells and cellular energy metabolism. Although glycolysis has been linked to immune functions, the mechanisms by which glycolysis regulates NLRP3 inflammasome activation remain unclear. Here, we demonstrate that mTORC1-induced glycolysis provides an essential mechanism for NLRP3 inflammasome activation. Moreover, we demonstrate that hexokinase 1 (HK1)-dependent glycolysis, under the regulation of mTORC1, represents a critical metabolic pathway for NLRP3 inflammasome activation. Downregulation of glycolysis by inhibition of Raptor/mTORC1 or HK1 suppressed both pro-IL-1β maturation and caspase-1 activation in macrophages in response to LPS and ATP. These results suggest that upregulation of HK1-dependent glycolysis by mTORC1 regulates NLRP3 inflammasome activation.
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Affiliation(s)
- Jong-Seok Moon
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College and New York-Presbyterian Hospital, New York, NY 10065, USA; Division of Pulmonary and Critical Care Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Shu Hisata
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College and New York-Presbyterian Hospital, New York, NY 10065, USA; Division of Pulmonary and Critical Care Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Mi-Ae Park
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Gina M DeNicola
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College and New York-Presbyterian Hospital, New York, NY 10065, USA
| | - Stefan W Ryter
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College and New York-Presbyterian Hospital, New York, NY 10065, USA; Division of Pulmonary and Critical Care Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Kiichi Nakahira
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College and New York-Presbyterian Hospital, New York, NY 10065, USA; Division of Pulmonary and Critical Care Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Augustine M K Choi
- Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College and New York-Presbyterian Hospital, New York, NY 10065, USA; Division of Pulmonary and Critical Care Medicine, Weill Cornell Medical College, New York, NY 10065, USA.
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Yu T, Jhun BS, Yoon Y. High-glucose stimulation increases reactive oxygen species production through the calcium and mitogen-activated protein kinase-mediated activation of mitochondrial fission. Antioxid Redox Signal 2011; 14:425-37. [PMID: 20518702 PMCID: PMC3025178 DOI: 10.1089/ars.2010.3284] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Increased production of reactive oxygen species (ROS) from mitochondria is the main cause of hyperglycemic complications. We previously showed that hyperglycemic conditions induce mitochondrial fragmentation that is causal for ROS overproduction. This study was to identify signaling components that induce mitochondrial fragmentation in high-glucose stimulation. We found that exposing cells to the high-glucose concentration evokes increases in cytosolic Ca(2+). Chelating Ca(2+) in the high-glucose medium prevented not only the Ca(2+) transient but also mitochondrial fragmentation and the ROS increase, indicating that the Ca(2+) influx across the plasma membrane is an upstream event governing mitochondrial fission and the ROS generation in high-glucose stimulation. We found that the high-glucose-induced Ca(2+) increase activates the mitogen-activated protein kinase extracellular signal-regulated kinase 1/2 (ERK1/2). The Ca(2+) chelation prevented the ERK1/2 activation, and inhibition of the ERK1/2 phosphorylation decreased mitochondrial fragmentation as well as ROS levels in high-glucose stimulation. In addition, the level of the mitochondrial fission protein dynamin-like protein 1 in mitochondria increased in high-glucose incubation in a Ca(2+)-dependent manner. In vitro kinase assays showed that ERK1/2 is capable of phosphorylating dynamin-like protein 1. These results demonstrate that high-glucose stimulation induces the activation of mitochondrial fission via signals mediated by intracellular Ca(2+) and ERK1/2.
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Affiliation(s)
- Tianzheng Yu
- Department of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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3
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Lee KH, Park JH, Won R, Lee H, Nam TS, Lee BH. Inhibition of hexokinase leads to neuroprotection against excitotoxicity in organotypic hippocampal slice culture. J Neurosci Res 2010; 89:96-107. [DOI: 10.1002/jnr.22525] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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4
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Robey RB, Hay N. Mitochondrial hexokinases, novel mediators of the antiapoptotic effects of growth factors and Akt. Oncogene 2006; 25:4683-96. [PMID: 16892082 DOI: 10.1038/sj.onc.1209595] [Citation(s) in RCA: 388] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cell survival has been closely linked to both trophic growth factor signaling and cellular metabolism. Such couplings have obvious physiologic and pathophysiologic implications, but their underlying molecular bases remain incompletely defined. As a common mediator of both the metabolic and anti-apoptotic effects of growth factors, the serine/threonine kinase Akt - also known as protein kinase B or PKB - is capable of regulating and coordinating these inter-related processes. The glucose dependence of the antiapoptotic effects of growth factors and Akt plus a strong correlation between Akt-regulated mitochondrial hexokinase association and apoptotic susceptibility suggest a major role for hexokinases in these effects. Mitochondrial hexokinases catalyse the first obligatory step of glucose metabolism and directly couple extramitochondrial glycolysis to intramitochondrial oxidative phosphorylation, and are thus well suited to play this role. The ability of Akt to regulate energy metabolism appears to have evolutionarily preceded the capacity to control cell survival. This suggests that Akt-dependent metabolic regulatory functions may have given rise to glucose-dependent antiapoptotic effects that evolved as an adaptive sensing system involving hexokinases and serve to ensure mitochondrial homeostasis, thereby coupling metabolism to cell survival. We hypothesize that the enlistment of Akt and hexokinase in the control of mammalian cell apoptosis evolved as a response to the recruitment of mitochondria to the apoptotic cascade. The central importance of mitochondrial hexokinases in cell survival also suggests that they may represent viable therapeutic targets in cancer.
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Affiliation(s)
- R B Robey
- Research and Development Service, White River Junction VA Medical Center, White River Junction, VT 05009-0001, USA
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5
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Affiliation(s)
- J E Wilson
- Department of Biochemistry, Michigan State University, East Lansing 48824
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da-Silva WS, Gómez-Puyou A, de Gómez-Puyou MT, Moreno-Sanchez R, De Felice FG, de Meis L, Oliveira MF, Galina A. Mitochondrial bound hexokinase activity as a preventive antioxidant defense: steady-state ADP formation as a regulatory mechanism of membrane potential and reactive oxygen species generation in mitochondria. J Biol Chem 2004; 279:39846-55. [PMID: 15247300 DOI: 10.1074/jbc.m403835200] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Brain hexokinase is associated with the outer membrane of mitochondria, and its activity has been implicated in the regulation of ATP synthesis and apoptosis. Reactive oxygen species (ROS) are by-products of the electron transport chain in mitochondria. Here we show that the ADP produced by hexokinase activity in rat brain mitochondria (mt-hexokinase) controls both membrane potential (Deltapsi(m)) and ROS generation. Exposing control mitochondria to glucose increased the rate of oxygen consumption and reduced the rate of hydrogen peroxide generation. Mitochondrial associated hexokinase activity also regulated Deltapsi(m), because glucose stabilized low Deltapsi(m) values in state 3. Interestingly, the addition of glucose 6-phosphate significantly reduced the time of state 3 persistence, leading to an increase in the Deltapsi(m) and in H(2)O(2) generation. The glucose analogue 2-deoxyglucose completely impaired H(2)O(2) formation in state 3-state 4 transition. In sharp contrast, the mt-hexokinase-depleted mitochondria were, in all the above mentioned experiments, insensitive to glucose addition, indicating that the mt-hexokinase activity is pivotal in the homeostasis of the physiological functions of mitochondria. When mt-hexokinase-depleted mitochondria were incubated with exogenous yeast hexokinase, which is not able to bind to mitochondria, the rate of H(2)O(2) generation reached levels similar to those exhibited by control mitochondria only when an excess of 10-fold more enzyme activity was supplemented. Hyperglycemia induced in embryonic rat brain cortical neurons increased ROS production due to a rise in the intracellular glucose 6-phosphate levels, which were decreased by the inclusion of 2-deoxyglucose, N-acetyl cysteine, or carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Taken together, the results presented here indicate for the first time that mt-hexokinase activity performed a key role as a preventive antioxidant against oxidative stress, reducing mitochondrial ROS generation through an ADP-recycling mechanism.
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Affiliation(s)
- Wagner Seixas da-Silva
- Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Rio de Janeiro 21941-590, Brazil
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7
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Taylor SW, Fahy E, Zhang B, Glenn GM, Warnock DE, Wiley S, Murphy AN, Gaucher SP, Capaldi RA, Gibson BW, Ghosh SS. Characterization of the human heart mitochondrial proteome. Nat Biotechnol 2003; 21:281-6. [PMID: 12592411 DOI: 10.1038/nbt793] [Citation(s) in RCA: 529] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2002] [Accepted: 01/14/2003] [Indexed: 11/08/2022]
Abstract
To gain a better understanding of the critical role of mitochondria in cell function, we have compiled an extensive catalogue of the mitochondrial proteome using highly purified mitochondria from normal human heart tissue. Sucrose gradient centrifugation was employed to partially resolve protein complexes whose individual protein components were separated by one-dimensional PAGE. Total in-gel processing and subsequent detection by mass spectrometry and rigorous bioinformatic analysis yielded a total of 615 distinct protein identifications. All protein pI values, molecular weight ranges, and hydrophobicities were represented. The coverage of the known subunits of the oxidative phosphorylation machinery within the inner mitochondrial membrane was >90%. A significant proportion of identified proteins are involved in signaling, RNA, DNA, and protein synthesis, ion transport, and lipid metabolism. The biochemical roles of 19% of the identified proteins have not been defined. This database of proteins provides a comprehensive resource for the discovery of novel mitochondrial functions and pathways.
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Affiliation(s)
- Steven W Taylor
- MitoKor, 11494 Sorrento Valley Road, San Diego, California 92121, USA.
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8
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Lynch RM, Carrington W, Fogarty KE, Fay FS. Metabolic modulation of hexokinase association with mitochondria in living smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 270:C488-99. [PMID: 8779911 DOI: 10.1152/ajpcell.1996.270.2.c488] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hexokinase isoform I binds to mitochondria of many cell types. It has been hypothesized that this association is regulated by changes in the concentrations of specific cellular metabolites. To study the distribution of hexokinase in living cells, fluorophore-labeled functional hexokinase I was prepared. After microinjection into A7r5 smooth muscle cells, hexokinase localized to distinct structures identified as mitochondria. The endogenous hexokinase demonstrated a similar distribution with the use of immunocytochemistry. 2-Deoxyglucose elicited an increase in glucose 6-phosphate (G-6-P) and a decrease in ATP levels and diminished hexokinase binding to mitochondria in single cells. 3-O-methylglucose elicited slowly developing decreases in all three parameters. In contrast, cyanide elicited a rapid decrease in both ATP and hexokinase binding. Analyses of changes in metabolite levels and hexokinase binding indicate a positive correlation between binding and cell energy state as monitored by ATP. On the other hand, only in the presence of 2-deoxyglucose was the predicted inverse correlation between binding and G-6-P observed. Unlike the relatively large changes in distribution observed with the fluorescent-injected hexokinase, cyanide caused only a small decrease in the localization of endogenous hexokinase with mitochondria. These findings suggest that changes in the concentrations of specific metabolites can alter the binding of hexokinase I to specific sites on mitochondria. Moreover, the apparent difference in sensitivity of injected and endogenous hexokinase to changes in metabolites may reflect the presence of at least two classes of binding mechanisms for hexokinase, with differential sensitivity to metabolites.
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Affiliation(s)
- R M Lynch
- Department of Physiology, University of Arizona, Tucson 85724, USA
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9
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Benz R. Permeation of hydrophilic solutes through mitochondrial outer membranes: review on mitochondrial porins. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1197:167-96. [PMID: 8031826 DOI: 10.1016/0304-4157(94)90004-3] [Citation(s) in RCA: 347] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- R Benz
- Lehrstuhl für Biotechnologie, Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg, Germany
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10
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Magnani M, Serafini G, Crinelli R, Antonelli A, Malatesta M, Gazzanelli G. Intracellular distribution of hexokinase in rabbit brain. Mol Cell Biochem 1993; 122:123-32. [PMID: 8232243 DOI: 10.1007/bf01076096] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Hexokinase in mammalian brain is particulate and usually considered to be bound to the outer mitochondrial membrane. Investigation of rabbit brain mitochondria prepared either by differential centrifugation and discontinuous density gradient centrifugation has provided evidence that this particulate fraction also contains endoplasmic vesicles and synaptosomes. Solubilization of the bound hexokinase by different combinations of detergents and metabolites has proved the existence of different hexokinase binding sites. Electron microscopic examination of hexokinase location by immuno-gold labelling techniques confirmed that hexokinase is indeed predominantly bound to mitochondria but that a significant proportion is also bound to non-mitochondrial membranes. Attempts to quantify this distribution were unsuccessful since different figures were obtained using anti-hexokinase IgG affinity purified on immobilized native or denatured hexokinase. Binding studies of the purified rabbit brain mitochondrial hexokinase to rabbit liver mitochondria and microsomes confirmed that in addition to a binding site on mitochondria there is another binding site on microsomes. The N-terminal sequence of hexokinase has been shown to be important for mitochondria binding and also for microsome binding. These results suggest that the intracellular localization of hexokinase in rabbit brain is not exclusively mitochondrial and that the metabolic role of this enzyme should be reconsidered by including a binding site on the endoplasmic reticulum.
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Affiliation(s)
- M Magnani
- Istituto di Chimica Biologica G. Fornaini, Università degli Studi, Urbino, Italy
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11
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Sorgato MC, Moran O. Channels in mitochondrial membranes: knowns, unknowns, and prospects for the future. Crit Rev Biochem Mol Biol 1993; 28:127-71. [PMID: 7683593 DOI: 10.3109/10409239309086793] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Rapid diffusion of hydrophilic molecules across the outer membrane of mitochondria has been related to the presence of a protein of 29 to 37 kDa, called voltage-dependent anion channel (VDAC), able to generate large aqueous pores when integrated in planar lipid bilayers. Functional properties of VDAC from different origins appear highly conserved in artificial membranes: at low transmembrane potentials, the channel is in a highly conducting state, but a raise of the potential (both positive and negative) reduces drastically the current and changes the ionic selectivity from slightly anionic to cationic. It has thus been suggested that VDAC is not a mere molecular sieve but that it may control mitochondrial physiology by restricting the access of metabolites of different valence in response to voltage and/or by interacting with a soluble protein of the intermembrane space. The latest application of the patch clamp and tip-dip techniques, however, has indicated both a different electric behavior of the outer membrane and that other proteins may play a role in the permeation of molecules. Biochemical studies, use of site-directed mutants, and electron microscopy of two-dimensional crystal arrays of VDAC have contributed to propose a monomeric beta barrel as the structural model of the channel. An important insight into the physiology of the inner membrane of mammalian mitochondria has come from the direct observation of the membrane with the patch clamp. A slightly anionic, voltage-dependent conductance of 107 pS and one of 9.7 pS, K(+)-selective and ATP-sensitive, are the best characterized at the single channel level. Under certain conditions, however, the inner membrane can also show unselective nS peak transitions, possibly arising from a cooperative assembly of multiple substrates.
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Affiliation(s)
- M C Sorgato
- Dipartimento di Chimica Biologica, Università di Padova, Italy
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12
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BeltrandelRio H, Wilson JE. Coordinated regulation of cerebral glycolytic and oxidative metabolism, mediated by mitochondrially bound hexokinase dependent on intramitochondrially generated ATP. Arch Biochem Biophys 1992; 296:667-77. [PMID: 1632653 DOI: 10.1016/0003-9861(92)90625-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) of rat brain mitochondria is associated with membrane regions thought to correspond to contact sites (regions of close interaction of the inner and outer mitochondrial membranes). Two intramitochondrial compartments of ATP also appear to be located at contact sites, and are dependent on oxidative phosphorylation for their generation. Neither of these compartments was associated with the intermembranal space containing adenylate kinase, nor was there detectable intramitochondrial compartmentation of ATP generated by the adenylate kinase reaction. Formation of these compartments was not dependent on the presence of bound hexokinase since equivalent amounts of compartmented ATP were found in mitochondria from which a major portion of the hexokinase had been removed by treatment with Glc-6-P. During active oxidative phosphorylation, mitochondrially bound hexokinase is totally dependent upon intramitochondrially compartmented ATP as a substrate. Both the levels of ATP in the intramitochondrial compartments and the rate of glucose phosphorylation by mitochondrially bound hexokinase were shown to be correlated with the rate of oxidative phosphorylation. This dependence of hexokinase on intramitochondrial ATP levels that reflect the status of mitochondrial oxidative metabolism provides a mechanism by which hexokinase can serve as a mediator, coordinating the rate at which glucose is introduced into the glycolytic pathway with terminal oxidative stages of metabolism and avoiding the accumulation of lactate which has been associated with toxic effects on the brain.
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Affiliation(s)
- H BeltrandelRio
- Department of Biochemistry, Michigan State University, East Lansing 48824
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13
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Arora KK, Parry DM, Pedersen PL. Hexokinase receptors: preferential enzyme binding in normal cells to nonmitochondrial sites and in transformed cells to mitochondrial sites. J Bioenerg Biomembr 1992; 24:47-53. [PMID: 1506408 DOI: 10.1007/bf00769530] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hexokinase plays an important role in normal glucose-utilizing tissues like brain and kidney, and an even more important role in highly malignant cancer cells where it is markedly overexpressed. In both cell types, normal and transformed, a significant portion of the total hexokinase activity is bound to particulate material that sediments upon differential centrifugation with the crude "mitochondrial" fraction. In the case of brain, particulate binding may constitute most of the total hexokinase activity of the cell, and in highly malignant tumor cells as much as 80 percent of the total. When a variety of techniques are rigorously applied to better define the particulate location of hexokinase within the crude "mitochondrial fraction," a striking difference is observed between the distribution of hexokinase in normal and transformed cells. Significantly, particulate hexokinase found in rat brain, kidney, or liver consistently distributes with nonmitochondrial membrane markers whereas the particulate hexokinase of highly glycolytic hepatoma cells distributes with outer mitochondrial membrane markers. These studies indicate that within normal tissues hexokinase binds preferentially to nonmitochondrial receptor sites but upon transformation of such cells to yield poorly differentiated, highly malignant tumors, the overexpressed enzyme binds preferentially to outer mitochondrial membrane receptors. These studies, taken together with the well-known observation that, once solubilized, the particulate hexokinase from a normal tissue can bind to isolated mitochondria, are consistent with the presence in normal tissues of at least two different types of particulate receptors for hexokinase with different subcellular locations. A model which explains this unique transformation-dependent shift in the intracellular location of hexokinase is proposed.
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Affiliation(s)
- K K Arora
- Department of Biological Chemistry, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205
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Uyeda K. Interactions of glycolytic enzymes with cellular membranes. CURRENT TOPICS IN CELLULAR REGULATION 1992; 33:31-46. [PMID: 1386802 DOI: 10.1016/b978-0-12-152833-1.50008-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- K Uyeda
- Pre-Clinical Science Unit, Department of Veterans Affairs Medical Center, Dallas, Texas
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15
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Arora KK, Fanciulli M, Pedersen PL. Glucose phosphorylation in tumor cells. Cloning, sequencing, and overexpression in active form of a full-length cDNA encoding a mitochondrial bindable form of hexokinase. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39352-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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16
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Parry DM, Pedersen PL. Glucose catabolism in brain. Intracellular localization of hexokinase. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)40158-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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17
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Gauthier T, Denis-Pouxviel C, Murat JC. Mitochondrial hexokinase from differentiated and undifferentiated HT29 colon cancer cells: effect of some metabolites on the bound/soluble equilibrium. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1990; 22:419-23. [PMID: 2338166 DOI: 10.1016/0020-711x(90)90146-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
1. Solubilization of mitochondrial bound hexokinase (HK), which represents 75-80% of the total enzyme activity in the cells, was investigated in freshly isolated mitochondria from undifferentiated (Glc+) or differentiated (Glc-) HT29 adenocarcinoma cells. In both models, the bound HK is almost completely released in vitro by 100 microM glucose 6-P (G 6-P). 2. Free ATP (5 mM) or palmitate (800 microM) produce a partial solubilization of bound HK, more markedly in the case of Glc- mitochondria. 3. Glucose or glucose 1-P are found unable to solubilize bound HK. Glucose 1,6-P2, 2-deoxyglucose 6-P or glucosamine 6-P can solubilize the enzyme but are less efficient than G 6-P. 4. Mg2+ and Pi are found to counteract the glucose 6-P induced solubilization of HK in both types of mitochondria. Taking into account the intracellular concentrations of these ions, this could in part explain why, in HT29 cells, HK is predominantly bound to the mitochondria.
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Affiliation(s)
- T Gauthier
- Institut de Physiologie, INSERM U 317, Université Paul Sabatier, Toulouse, France
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18
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Gauthier T, Denis-Pouxviel C, Paris H, Murat JC. Study on ATP-generating system and related hexokinase activity in mitochondria isolated from undifferentiated or differentiated HT29 adenocarcinoma cells. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 975:231-8. [PMID: 2525930 DOI: 10.1016/s0005-2728(89)80253-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The functional properties of mitochondria bound hexokinase are compared in two subpopulations of the HT29 human colon cancer cell-line: (1) the HT29 Glc+ cells, cultured in the presence of glucose, which are poorly differentiated and highly glycolytic and (2) the HT29 Glc- cells, adapted to grow in a glucose-free medium, which are 'enterocyte-like' differentiated and less glycolytic when given glucose (Zweibaum et al. (1985) J. Cell Physiol. 122, 21-28). The activities of hexokinase, phosphofructokinase-1 and pyruvate kinase are found to be twice as high in Glc+ cells when compared to Glc- cells. Besides, the respiration rate is decreased in Glc+ cells compared to Glc- cells. These results correlate with the higher glycolytic rate in Glc+ cells. In many tissues, it has been shown that the binding of hexokinase to the mitochondrial outer membrane allows a preferential utilization of the ATP generated by oxidative phosphorylation which, in turn, is activated by immediate restitution of ADP. In highly glycolytic cancer cells, although a large fraction of hexokinase is bound to the mitochondria, the existence of such a channeling of nucleotides is still poorly documented. The rates of glucose phosphorylation by bound hexokinase were investigated in mitochondria isolated from both Glc+ and Glc- cells either with exogenous ATP or with ATP generated by mitochondria supplied with ADP and succinate (endogenous ATP). Diadenosine pentaphosphate (Ado2P5), oligomycin and carboxyatractyloside (CAT) were used in combination or separately as metabolic inhibitors of adenylate kinase, ATP synthase and ATP/ADP translocator, respectively. Exogenous ATP appears to be 6.5-times more efficient than endogenous ATP in supporting hexokinase activity in the mitochondria from Glc+ cells and only 1.8-times cells. The rate of oxidative phosphorylation being higher in mitochondria from Glc- cells, hexokinase activity is higher in this model when ATP is generated by respiration. Furthermore, in Glc+ mitochondria, the adenylate kinase reaction appears to be an important source of endogenous ATP for bound hexokinase, while, in Glc- mitochondria, hexokinase activity is almost totally dependent on the ATP generated by oxidative phosphorylation. This result might be explained by our previous finding that mitochondria from Glc+ cells lack contact sites between outer and inner membrane, whereas numerous contacts were observed in mitochondria from Glc- cells (Denis-Pouxviel et al. (1987) Biochim. Biophys. Acta 902, 335-348).
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Affiliation(s)
- T Gauthier
- INSERM U 317, Institut de Physiologie, Université Paul Sabatier, Toulouse, France
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19
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Functional significance of mitochondrial bound hexokinase in tumor cell metabolism. Evidence for preferential phosphorylation of glucose by intramitochondrially generated ATP. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)77853-3] [Citation(s) in RCA: 234] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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20
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Abstract
Dicarboxylic porphyrins were reported to be potent inhibitors of the binding of benzodiazepines to peripheral drug receptors in mitochondria, but the reverse does not appear to be true. Moreover, the photosensitization of mitochondria by the tumor-localizing porphyrin dimer/oligomer fraction of 'HPD' was not inhibited by benzodiazepines in cell culture.
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Affiliation(s)
- D Kessel
- Department of Medicine (Hematology/Oncology), Wayne State University School of Medicine, Detroit, MI
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21
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Magnani M, Stocchi V, Serafini G, Chiarantini L, Fornaini G. Purification, properties, and evidence for two subtypes of human placenta hexokinase type I. Arch Biochem Biophys 1988; 260:388-99. [PMID: 3341751 DOI: 10.1016/0003-9861(88)90462-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In human placenta 85% of total hexokinase activity (EC 2.7.1.1) was found in a soluble form. Of this, 70% is hexokinase type I while the remaining 30% is hexokinase type II. All the bound hexokinase is type I. Soluble hexokinase I was purified 11,000-fold by a combination of ion-exchange chromatography, affinity chromatography, and dye-ligand chromatography. The specific activity was 190 units/mg protein with a 75% yield. The enzyme shows only one band in nondenaturing polyacrylamide gel electrophoresis that stains for protein and enzymatic activity; however, two components (with Mr 112,000 and 103,000) were constantly seen in sodium dodecyl sulfate-gel electrophoresis. Many attempts were made to separate these two proteins under native conditions; however, only one peak of activity was obtained when the enzyme was submitted to gel filtration (Mr 118,000), preparative isoelectric focusing (pI 5.9), anion-exchange chromatography, hydroxylapatite chromatography, and affinity chromatography on immobilized dyes and immobilized glucosamine. The high and low molecular weight hexokinases show the same isoelectric point under denaturing conditions as determined by two-dimensional gel electrophoresis. Each hexokinase subtype was obtained by preparative sodium dodecyl sulfate electrophoresis followed by electroelution. Monospecific antibodies raised in rabbits against electroeluted high and low molecular weight hexokinases were not able to recognize the native enzymes but each of them detected both hexokinases on immunoblots. Amino acid compositions and peptide mapping by limited proteolysis of the high and low molecular weight hexokinases were also performed and suggested a strong homology between these two subtypes of human hexokinase I.
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Affiliation(s)
- M Magnani
- Istituto di Chimica Biologica, Università degli Studi di Urbino, Italy
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Denis-Pouxviel C, Riesinger I, Bühler C, Brdiczka D, Murat JC. Regulation of mitochondrial hexokinase in cultured HT 29 human cancer cells. An ultrastructural and biochemical study. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 902:335-48. [PMID: 3620464 DOI: 10.1016/0005-2736(87)90202-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The involvement of the mitochondrial bound hexokinase in aerobic glycolysis was investigated in two subpopulations of the HT 29 human colon cancer cell line: a poorly differentiated one with high aerobic lactate production (referred as undifferentiated or standard cells), and an enterocyte-like differentiated one with lower lactate production (referred as differentiated or Glc- cells). After mild digitonin treatment, 85% of the total cellular hexokinase activity remained in the particulate fraction in both cell types. In both cases mitochondria appeared to be tightly coupled but the Glc- cells exhibited a significantly higher oxidation rate in the presence of glucose. Electron microscopy of freeze-fractured cells revealed the absence of contacts between the two limiting mitochondrial membranes in the highly glycolytic standard cells, whereas the contacts were present in the Glc- cells. Furthermore, we investigated the functional relationship between bound hexokinase (as hexokinase-porin complex) and the inner compartment of mitochondria isolated from standard and Glc- HT 29 cells. In contrast to the differentiated cells the hexokinase in undifferentiated standard cells was not functionally coupled to the oxidative phosphorylation. This suggests that the high rate of lactate formation in neoplastic cells is not caused by an increase of particulate hexokinase activity but rather by a disregulation of the hexokinase-porin complex caused by the absence of contact sites between the two mitochondrial membranes. In agreement with this interpretation, the hexokinase-porin complex could be completely removed by digitonin treatment in standard HT 29 cells, while this was not possible in mitochondria from Glc- cells.
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Abstract
The outer mitochondrial membrane contains a pore structure which is composed of a 30,000 Da protein, porin. The pore has an internal diameter of 2 nm and exhibits a molecular-sieving exclusion limit between 3000 and 6000 Da. These pores, therefore, provide the exit/entrance port for metabolites moving between mitochondria and the cytosol. Hexokinase binds to porin on the outer surface of mitochondria. The location of hexokinase has evoked a number of theories in which bound hexokinase is given a central role in regulating glycolysis, and, perhaps, the metabolic communication between oxidative and glycolytic metabolism. This is of particular importance in rapidly growing tumor cells in which the aerobic production of lactate and hexokinase activity are highly induced. In the present paper, we summarize the suggested roles of the outer membrane and bound hexokinase in regulation glycolysis of tumor cells. Experiments attempting to elucidate the role of hexokinase binding in the regulation of tumor cell metabolism are presented.
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Abstract
The interactions of the isozymes of hexokinase with cellular structure have been studied in the major tissues of the mouse during development. Overall, these data provide a clear indication that interactions between hexokinase and cellular structure are appreciable in all major tissues and at all stages of development, and an analysis of the isozyme status of the enzyme in both soluble and bound compartments has been effected. Further evidence in support of the already well documented interaction of hexokinase I to subcellular material in adult brain and kidney tissues is provided and extended to show that such interactions are extensive in both these tissues throughout development. In addition, evidence is provided that considerable hexokinase II activity is present in mouse foetal tissues in both the soluble and bound fractions and this isozyme is also shown to be the predominant "bound" form of the enzyme in adult skeletal muscle. By contrast, hexokinase III and IV are shown to be largely located in the cytosolic fraction of liver. The metabolic implications of these enzyme-structural interactions during development are discussed, as is the possibility of a functional linkage between hexokinase, which is bound to the mitochondria, and other enzymic components of the glycolytic sequence.
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