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Effect of pH on the activity of ice-binding protein from Marinomonas primoryensis. Extremophiles 2020; 25:1-13. [PMID: 33090301 DOI: 10.1007/s00792-020-01206-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022]
Abstract
The ability of an ice-binding protein (IBP) from Marinomonas primoryensis (MpIBP) to influence ice crystal growth and structure in nonphysiological pH environments was investigated in this work. The ability for MpIBP to retain ice interactivity under stressed environmental conditions was determined via (1) a modified splat assay to determine ice recrystallization inhibition (IRI) of polycrystalline ice and (2) nanoliter osmometry to evaluate the ability of MpIBP to dynamically shape the morphology of a single ice crystal. Circular dichroism (CD) was used to relate the IRI and DIS activity of MpIBP to secondary structure. The results illustrate that MpIBP secondary structure was stable between pH 6 and pH 10. It was found that MpIBP did not interact with ice at pH ≤ 4 or pH ≥ 13. At 6 ≤ pH ≥ 12 MpIBP exhibited a reduction in grain size of ice crystals as compared to control solutions and demonstrated dynamic ice shaping at 6 ≤ pH ≥ 10. The results substantiate that MpIBP retains some secondary structure and function in non-neutral pH environments; thereby, enabling its potential utility in nonphysiological materials science and engineering applications.
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Pandhare A, Stuebler AG, Pirayesh E, Jansen M. A modified clear-native polyacrylamide gel electrophoresis technique to investigate the oligomeric state of MBP-5-HT 3A-intracellular domain chimeras. Protein Expr Purif 2018; 153:45-52. [PMID: 30130580 DOI: 10.1016/j.pep.2018.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/17/2018] [Accepted: 08/18/2018] [Indexed: 11/27/2022]
Abstract
The main principles of higher-order protein oligomerization are elucidated by many structural and biophysical studies. An astonishing number of proteins self-associate to form dimers or higher-order quaternary structures which further interact with other biomolecules to elicit complex cellular responses. In this study, we describe a simple and convenient approach to determine the oligomeric state of purified protein complexes that combines implementation of a novel form of clear-native gel electrophoresis and size exclusion chromatography in line with multi-angle light scattering. Here, we demonstrate the accuracy of this ensemble approach by characterizing the previously established pentameric state of the intracellular domain of serotonin type 3A (5-HT3A) receptors.
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Affiliation(s)
- Akash Pandhare
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
| | - Antonia G Stuebler
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Elham Pirayesh
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Michaela Jansen
- Department of Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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3
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Gallagher SR. One-Dimensional Electrophoresis Using Nondenaturing Conditions. ACTA ACUST UNITED AC 2018; 94:e73. [DOI: 10.1002/cpps.73] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Abstract
Protein-protein interactions and multi-protein assemblies are inherent features of proteomes, involving soluble and membrane proteins. This imparts structural and functional heterogeneity to the proteome. One needs to consider this aspect while studying changes in abundance or activities of proteins in response to any physiological stimulus. Abundance changes in components of a given proteome can be best visualized and quantified using electrophoresis-based approaches. Here, we describe the method of Blue Native Difference Gel Electrophoresis (BN DIGE) to quantify abundance changes in proteins in the context of protein-protein interactions. This method confers an additional advantage to monitor quantitative changes in membrane proteins, which otherwise is a difficult task.
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Ramos-León F, Mariscal V, Battchikova N, Aro EM, Flores E. Septal protein SepJ from the heterocyst-forming cyanobacterium Anabaena forms multimers and interacts with peptidoglycan. FEBS Open Bio 2017; 7:1515-1526. [PMID: 28979840 PMCID: PMC5623728 DOI: 10.1002/2211-5463.12280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/20/2017] [Accepted: 07/31/2017] [Indexed: 12/30/2022] Open
Abstract
Heterocyst‐forming cyanobacteria grow as filaments that can be hundreds of cells long. Proteinaceous septal junctions provide cell–cell binding and communication functions in the filament. In Anabaena sp. strain PCC 7120, the SepJ protein is important for the formation of septal junctions. SepJ consists of integral membrane and extramembrane sections – the latter including linker and coiled‐coil domains. SepJ (predicted MW, 81.3 kDa) solubilized from Anabaena membranes was found in complexes of about 296–334 kDa, suggesting that SepJ forms multimeric complexes. We constructed an Anabaena strain producing a double‐tagged SepJ protein (SepJ‐GFP‐His10) and isolated the tagged protein by a two‐step affinity chromatography procedure. Analysis of the purified protein preparation provided no indication of the presence of specific SepJ partners, but suggested that SepJ is processed to remove an N‐terminal fragment. Additionally, pull‐down experiments showed that His6‐tagged versions of SepJ and of the SepJ coiled‐coil domain interact with Anabaena peptidoglycan (PG). Our results indicate that SepJ forms multimers, that it interacts with PG, and that the coiled‐coil domain is involved in this interaction. These observations support the idea that SepJ is a component of the septal junctions that join the cells in the Anabaena filament.
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Affiliation(s)
- Félix Ramos-León
- Instituto de Bioquímica Vegetal y Fotosíntesis CSIC Universidad de Sevilla Spain
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis CSIC Universidad de Sevilla Spain
| | - Natalia Battchikova
- Laboratory of Molecular Plant Biology Department of Biochemistry University of Turku Finland
| | - Eva-Mari Aro
- Laboratory of Molecular Plant Biology Department of Biochemistry University of Turku Finland
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis CSIC Universidad de Sevilla Spain
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Luo X, Wu J, Jin Z, Yan LJ. Non-Gradient Blue Native Polyacrylamide Gel Electrophoresis. ACTA ACUST UNITED AC 2017; 87:19.29.1-19.29.12. [PMID: 28150881 DOI: 10.1002/cpps.21] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gradient blue native polyacrylamide gel electrophoresis (BN-PAGE) is a well established and widely used technique for activity analysis of high-molecular-weight proteins, protein complexes, and protein-protein interactions. Since its inception in the early 1990s, a variety of minor modifications have been made to this gradient gel analytical method. Here we provide a major modification of the method, which we call non-gradient BN-PAGE. The procedure, similar to that of non-gradient SDS-PAGE, is simple because there is no expensive gradient maker involved. The non-gradient BN-PAGE protocols presented herein provide guidelines on the analysis of mitochondrial protein complexes, in particular, dihydrolipoamide dehydrogenase (DLDH) and those in the electron transport chain. Protocols for the analysis of blood esterases or mitochondrial esterases are also presented. The non-gradient BN-PAGE method may be tailored for analysis of specific proteins according to their molecular weight regardless of whether the target proteins are hydrophobic or hydrophilic. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Xiaoting Luo
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas.,Department of Biochemistry and Molecular Biology, Gannan Medical University, Ganzhou, Jiangxi Province, China
| | - Jinzi Wu
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Zhen Jin
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Liang-Jun Yan
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas.,Corresponding author
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Santamaría-Gómez J, Ochoa de Alda JAG, Olmedo-Verd E, Bru-Martínez R, Luque I. Sub-Cellular Localization and Complex Formation by Aminoacyl-tRNA Synthetases in Cyanobacteria: Evidence for Interaction of Membrane-Anchored ValRS with ATP Synthase. Front Microbiol 2016; 7:857. [PMID: 27375579 PMCID: PMC4893482 DOI: 10.3389/fmicb.2016.00857] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/23/2016] [Indexed: 01/09/2023] Open
Abstract
tRNAs are charged with cognate amino acids by aminoacyl-tRNA synthetases (aaRSs) and subsequently delivered to the ribosome to be used as substrates for gene translation. Whether aminoacyl-tRNAs are channeled to the ribosome by transit within translational complexes that avoid their diffusion in the cytoplasm is a matter of intense investigation in organisms of the three domains of life. In the cyanobacterium Anabaena sp. PCC 7120, the valyl-tRNA synthetase (ValRS) is anchored to thylakoid membranes by means of the CAAD domain. We have investigated whether in this organism ValRS could act as a hub for the nucleation of a translational complex by attracting other aaRSs to the membranes. Out of the 20 aaRSs, only ValRS was found to localize in thylakoid membranes whereas the other enzymes occupied the soluble portion of the cytoplasm. To investigate the basis for this asymmetric distribution of aaRSs, a global search for proteins interacting with the 20 aaRSs was conducted. The interaction between ValRS and the FoF1 ATP synthase complex here reported is of utmost interest and suggests a functional link between elements of the gene translation and energy production machineries.
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Affiliation(s)
- Javier Santamaría-Gómez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | | | - Elvira Olmedo-Verd
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | - Roque Bru-Martínez
- Department of Agrochemistry and Biochemistry, Faculty of Science, University of AlicanteAlicante, Spain
| | - Ignacio Luque
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
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Morrow G, Kim HJ, Pellerito O, Bourrelle-Langlois M, Le Pécheur M, Groebe K, Tanguay RM. Changes in Drosophila mitochondrial proteins following chaperone-mediated lifespan extension confirm a role of Hsp22 in mitochondrial UPR and reveal a mitochondrial localization for cathepsin D. Mech Ageing Dev 2016; 155:36-47. [PMID: 26930296 DOI: 10.1016/j.mad.2016.02.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 01/20/2016] [Accepted: 02/25/2016] [Indexed: 10/22/2022]
Abstract
Hsp22 is a small mitochondrial heat shock protein (sHSP) preferentially up-regulated during aging in Drosophila melanogaster. Its developmental expression is strictly regulated and it is rapidly induced in conditions of stress. Hsp22 is one of the few sHSP to be localized inside mitochondria, and is the first sHSP to be involved in the mitochondrial unfolding protein response (UPR(MT)) together with Hsp60, mitochondrial Hsp70 and TRAP1. The UPR(MT) is a pro-longevity mechanism, and interestingly Hsp22 over-expression by-itself increases lifespan and resistance to stress. To unveil the effect of Hsp22 on the mitochondrial proteome, comparative IEF/SDS polyacrylamide 2D gels were done on mitochondria from Hsp22+ flies and controls. Among the proteins influenced by Hsp22 expression were proteins from the electron transport chain (ETC), the TCA cycle and mitochondrial Hsp70. Hsp22 co-migrates with ETC components and its over-expression is associated with an increase in mitochondrial protease activity. Interestingly, the only protease that showed significant changes upon Hsp22 over-expression in the comparative IEF/SDS-PAGE analysis was cathepsin D, which is localized in mitochondria in addition to lysosome in D. melanogaster as evidenced by cellular fractionation. Together the results are consistent with a role of Hsp22 in the UPR(MT) and in mitochondrial proteostasis.
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Affiliation(s)
- Geneviève Morrow
- Laboratoire de Génétique Cellulaire et Développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Québec, G1V 0A6, Canada
| | - Hyun-Ju Kim
- Laboratoire de Génétique Cellulaire et Développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Québec, G1V 0A6, Canada
| | - Ornella Pellerito
- Laboratoire de Génétique Cellulaire et Développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Québec, G1V 0A6, Canada
| | - Maxime Bourrelle-Langlois
- Laboratoire de Génétique Cellulaire et Développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Québec, G1V 0A6, Canada
| | - Marie Le Pécheur
- Laboratoire de Génétique Cellulaire et Développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Québec, G1V 0A6, Canada
| | | | - Robert M Tanguay
- Laboratoire de Génétique Cellulaire et Développementale, Département de biologie moléculaire, biochimie médicale et pathologie, Institut de Biologie Intégrative et des Systèmes (IBIS) and PROTEO, Université Laval, Québec, G1V 0A6, Canada.
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Kuter K, Kratochwil M, Berghauzen-Maciejewska K, Głowacka U, Sugawa MD, Ossowska K, Dencher NA. Adaptation within mitochondrial oxidative phosphorylation supercomplexes and membrane viscosity during degeneration of dopaminergic neurons in an animal model of early Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2016; 1862:741-753. [PMID: 26844379 DOI: 10.1016/j.bbadis.2016.01.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/27/2016] [Accepted: 01/29/2016] [Indexed: 01/02/2023]
Abstract
In Parkinson's disease (PD) motor symptoms are not observed until loss of 70% of dopaminergic neurons in substantia nigra (SN), preventing early diagnosis. Mitochondrial dysfunction was indicated in neuropathological process already at early PD stages. Aging and oxidative stress, the main factors in PD pathogenesis, cause membrane stiffening, which could influence functioning of membrane-bound oxidative phosphorylation (OxPhos) complexes (Cxs) in mitochondria. In 6-OHDA rat model, medium-sized dopaminergic lesion was used to study mitochondrial membrane viscosity and changes at the level of OxPhos Cxs and their higher assembled states-supercomplexes (SCxs), during the early degeneration processes and after it. We observed loss of dopaminergic phenotype in SN and decreased dopamine level in striatum (STR) before actual death of neurons in SN. Behavioural deficits induced by lesion were reversed despite progressing neurodegeneration. Along with degeneration process in STR, mitochondrial Cx I performance and amount decreased in almost all forms of SCxs. Also, progressing decrease of Cx IV performance in SCxs (I1III2IV3-1, I1IV2-1) in STR was observed during degeneration. In SN, SCxs containing Cx I increased protein amount and a shifted individual Cx I1 into superassembled states. Importantly, mitochondrial membrane viscosity changed in parallel with altered SCxs performance. We show for the first time changes at the level of mitochondrial membrane viscosity influencing SCxs function after dopaminergic system degeneration. It implicates that altered mitochondrial membrane viscosity could play an important role in regulation of mitochondria functioning and pathomechanisms of PD. The data obtained are also discussed in relation to compensatory processes observed.
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Affiliation(s)
- Katarzyna Kuter
- Department of Neuropsychopharmacology, Polish Academy of Sciences, Smętna St. 12, 31-343 Kraków, Poland.
| | - Manuela Kratochwil
- Physical Biochemistry, Department of Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany
| | | | - Urszula Głowacka
- Department of Neuropsychopharmacology, Polish Academy of Sciences, Smętna St. 12, 31-343 Kraków, Poland
| | - Michiru D Sugawa
- Physical Biochemistry, Department of Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany; Clinical Neurobiology, Charité-Universitätsmedizin, D-12203 Berlin, Germany
| | - Krystyna Ossowska
- Department of Neuropsychopharmacology, Polish Academy of Sciences, Smętna St. 12, 31-343 Kraków, Poland
| | - Norbert A Dencher
- Physical Biochemistry, Department of Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Str. 4, D-64287 Darmstadt, Germany
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Drosophila melanogaster mitochondrial Hsp22: a role in resistance to oxidative stress, aging and the mitochondrial unfolding protein response. Biogerontology 2015; 17:61-70. [DOI: 10.1007/s10522-015-9591-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 07/01/2015] [Indexed: 12/27/2022]
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11
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The bc:caa3 supercomplexes from the Gram positive bacterium Bacillus subtilis respiratory chain: A megacomplex organization? Arch Biochem Biophys 2013; 537:153-60. [DOI: 10.1016/j.abb.2013.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 11/19/2022]
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12
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Lenaz G, Genova ML. Supramolecular Organisation of the Mitochondrial Respiratory Chain: A New Challenge for the Mechanism and Control of Oxidative Phosphorylation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:107-44. [DOI: 10.1007/978-1-4614-3573-0_5] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Crystal structure of the NADP-dependent mannitol dehydrogenase from Cladosporium herbarum: Implications for oligomerisation and catalysis. Biochimie 2010; 92:985-93. [DOI: 10.1016/j.biochi.2010.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 04/19/2010] [Indexed: 11/15/2022]
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14
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Wernicke C, Hellmann J, Zieba B, Kuter K, Ossowska K, Frenzel M, Dencher NA, Rommelspacher H. 9-Methyl-beta-carboline has restorative effects in an animal model of Parkinson's disease. Pharmacol Rep 2010; 62:35-53. [PMID: 20360614 DOI: 10.1016/s1734-1140(10)70241-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 02/08/2009] [Indexed: 12/19/2022]
Abstract
In a previous study, a primary culture of midbrain cells was exposed to 9-methyl-beta-carboline for 48 h, which caused an increase in the number of tyrosine hydroxylase-positive cells. Quantitative RT-PCR revealed increased transcription of genes participating in the maturation of dopaminergic neurons. These in vitro findings prompted us to investigate the restorative actions of 9-methyl-beta-carboline in vivo. The compound was delivered for 14 days into the left cerebral ventricle of rats pretreated with the neurotoxin 1-methyl-4-phenyl-pyridinium ion (MPP+) for 28 days applying a dose which lowered dopamine by approximately 50%. Interestingly, 9-methyl-beta-carboline reversed the dopamine-lowering effect of the neurotoxin in the left striatum. Stereological counts of tyrosine hydroxylase-immunoreactive cells in the substantia nigra revealed that the neurotoxin caused a decrease in the number of those cells. However, when treated subsequently with 9-methyl-beta-carboline, the number reached normal values. In search of an explanation for the restorative activity, we analyzed the complexes that compose the respiratory chain in striatal mitochondria by 2-dimension gel electrophoresis followed by MALDI-TOF peptide mass fingerprinting.We found no changes in the overall composition of the complexes. However, the activity of complex I was increased by approximately 80% in mitochondria from rats treated with MPP+ and 9-methyl-beta-carboline compared to MPP+ and saline and to sham-operated rats, as determined by measurements of nicotinamide adenine dinucleotide dehydrogenase activity. Microarray technology and single RT-PCR revealed the induction of neurotrophins: brain-derived neurotrophic factor, conserved dopamine neurotrophic factor, cerebellin 1 precursor protein, and ciliary neurotrophic factor. Selected western blots yielded consistent results. The findings demonstrate restorative effects of 9-methyl-beta-carboline in an animal model of Parkinson's disease that improve the effectiveness of the respiratory chain and promote the transcription and expression of neurotrophin-related genes.
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Affiliation(s)
- Catrin Wernicke
- Department of Psychiatry, CCM, Charité-University Medicine Berlin, Dorotheenstr. 94, 10117 Berlin, Germany.
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Maas MFPM, Krause F, Dencher NA, Sainsard-Chanet A. Respiratory complexes III and IV are not essential for the assembly/stability of complex I in fungi. J Mol Biol 2008; 387:259-69. [PMID: 19111556 DOI: 10.1016/j.jmb.2008.12.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 12/08/2008] [Accepted: 12/10/2008] [Indexed: 11/29/2022]
Abstract
The functional relevance of respiratory supercomplexes in various eukaryotes including mammals, plants, and fungi is hitherto poorly elucidated. However, substantial evidence indicates as a major role the assembly and/or stabilization of mammalian complex I by supercomplex formation with complexes III and IV. Here, we demonstrate by using native electrophoresis that the long-lived Podospora anserina mutant Cyc1-1, respiring exclusively via the alternative oxidase (AOX), lacks an assembled complex III and possesses complex I partially assembled with complex IV into a supercomplex. This resembles the situation in complex-IV-deficient mutants displaying a corresponding phenotype but possessing I-III supercomplexes instead, suggesting that either complex III or complex IV is in a redundant manner necessary for assembly/stabilization of complex I as previously shown in mammals. To corroborate this notion, we constructed the double mutant Cyc1-1,Cox5::ble. Surprisingly, this mutant lacking both complexes III and IV is viable and essentially a phenocopy of mutant Cyc1-1 including the reversal of the phenotype towards wild-type-like characteristics by the several-fold overexpression of the AOX in mutant Cyc1-1,Cox5::ble(Gpd-Aox). Fungal specific features (not found in mammals) that must be responsible for assembly/stabilization of fungal complex I when complexes III and IV are absent, such as the presence of the AOX and complex I dimerization, are addressed and discussed. These intriguing results unequivocally prove that complexes III and IV are dispensable for assembly/stability of complex I in fungi contrary to the situation in mammals, thus highlighting the imperative to unravel the biogenesis of complex I as well as the true supramolecular organization of the respiratory chain and its functional significance in a variety of model eukaryotes. In summary, we present the first obligatorily aerobic eukaryote with an artificial, simultaneous lack of the respiratory complexes III and IV.
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Affiliation(s)
- Marc F P M Maas
- Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, 91198 Gif sur Yvette, France
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