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Dabbaghizadeh A, Morrow G, Amer YO, Chatelain EH, Pichaud N, Tanguay RM. Identification of proteins interacting with the mitochondrial small heat shock protein Hsp22 of Drosophila melanogaster: Implication in mitochondrial homeostasis. PLoS One 2018; 13:e0193771. [PMID: 29509794 PMCID: PMC5839585 DOI: 10.1371/journal.pone.0193771] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 02/16/2018] [Indexed: 12/17/2022] Open
Abstract
The small heat shock protein (sHsp) Hsp22 from Drosophila melanogaster (DmHsp22) is part of the family of sHsps in this diptera. This sHsp is characterized by its presence in the mitochondrial matrix as well as by its preferential expression during ageing. Although DmHsp22 has been demonstrated to be an efficient in vitro chaperone, its function within mitochondria in vivo remains largely unknown. Thus, determining its protein-interaction network (interactome) in the mitochondrial matrix would help to shed light on its function(s). In the present study we combined immunoaffinity conjugation (IAC) with mass spectroscopy analysis of mitochondria from HeLa cells transfected with DmHsp22 in non-heat shock condition and after heat shock (HS). 60 common DmHsp22-binding mitochondrial partners were detected in two independent IACs. Immunoblotting was used to validate interaction between DmHsp22 and two members of the mitochondrial chaperone machinery; Hsp60 and Hsp70. Among the partners of DmHsp22, several ATP synthase subunits were found. Moreover, we showed that expression of DmHsp22 in transiently transfected HeLa cells increased maximal mitochondrial oxygen consumption capacity and ATP contents, providing a mechanistic link between DmHsp22 and mitochondrial functions.
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Affiliation(s)
- Afrooz Dabbaghizadeh
- Laboratoire de Génétique Cellulaire et Développementale, IBIS and PROTEO, Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Geneviève Morrow
- Laboratoire de Génétique Cellulaire et Développementale, IBIS and PROTEO, Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Yasmine Ould Amer
- Laboratoire de Signalisation Mitochondriale, Département de Biologie, Université de Moncton, Moncton, NB, Canada
| | - Etienne Hebert Chatelain
- Laboratoire de Signalisation Mitochondriale, Département de Biologie, Université de Moncton, Moncton, NB, Canada
| | - Nicolas Pichaud
- Laboratoire de Biochimie et Physiologie Comparée, Département de Chimie et Biochimie, Université de Moncton, Moncton, NB, Canada
| | - Robert M Tanguay
- Laboratoire de Génétique Cellulaire et Développementale, IBIS and PROTEO, Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Faculté de Médecine, Université Laval, Québec, Canada
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Chaturvedi D, Mahalakshmi R. Transmembrane β-barrels: Evolution, folding and energetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2467-2482. [PMID: 28943271 DOI: 10.1016/j.bbamem.2017.09.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022]
Abstract
The biogenesis of transmembrane β-barrels (outer membrane proteins, or OMPs) is an elaborate multistep orchestration of the nascent polypeptide with translocases, barrel assembly machinery, and helper chaperone proteins. Several theories exist that describe the mechanism of chaperone-assisted OMP assembly in vivo and unassisted (spontaneous) folding in vitro. Structurally, OMPs of bacterial origin possess even-numbered strands, while mitochondrial β-barrels are even- and odd-stranded. Several underlying similarities between prokaryotic and eukaryotic β-barrels and their folding machinery are known; yet, the link in their evolutionary origin is unclear. While OMPs exhibit diversity in sequence and function, they share similar biophysical attributes and structure. Similarly, it is important to understand the intricate OMP assembly mechanism, particularly in eukaryotic β-barrels that have evolved to perform more complex functions. Here, we deliberate known facets of β-barrel evolution, folding, and stability, and attempt to highlight outstanding questions in β-barrel biogenesis and proteostasis.
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Affiliation(s)
- Deepti Chaturvedi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
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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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4
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Guerreiro JF, Sampaio-Marques B, Soares R, Coelho AV, Leão C, Ludovico P, Sá-Correia I. Mitochondrial proteomics of the acetic acid - induced programmed cell death response in a highly tolerant Zygosaccharomyces bailii - derived hybrid strain. MICROBIAL CELL 2016; 3:65-78. [PMID: 28357336 PMCID: PMC5349105 DOI: 10.15698/mic2016.02.477] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Very high concentrations of acetic acid at low pH induce programmed cell death
(PCD) in both the experimental model Saccharomyces cerevisiae
and in Zygosaccharomyces bailii, the latter being considered
the most problematic acidic food spoilage yeast due to its remarkable intrinsic
resistance to this food preservative. However, while the mechanisms underlying
S. cerevisiae PCD induced by acetic acid have been
previously examined, the corresponding molecular players remain largely unknown
in Z. bailii. Also, the reason why acetic acid concentrations
known to be necrotic for S. cerevisiae induce PCD with an
apoptotic phenotype in Z. bailii remains to be elucidated. In
this study, a 2-DE-based expression mitochondrial proteomic analysis was
explored to obtain new insights into the mechanisms involved in PCD in the
Z. bailii derived hybrid strain ISA1307. This allowed the
quantitative assessment of expression of protein species derived from each of
the parental strains, with special emphasis on the processes taking place in the
mitochondria known to play a key role in acetic acid - induced PCD. A marked
decrease in the content of proteins involved in mitochondrial metabolism, in
particular, in respiratory metabolism (Cor1, Rip1, Lpd1, Lat1 and Pdb1), with a
concomitant increase in the abundance of proteins involved in fermentation
(Pdc1, Ald4, Dld3) was registered. Other differentially expressed identified
proteins also suggest the involvement of the oxidative stress response, protein
translation, amino acid and nucleotide metabolism, among other processes, in the
PCD response. Overall, the results strengthen the emerging concept of the
importance of metabolic regulation of yeast PCD.
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Affiliation(s)
- Joana F Guerreiro
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga 4710-057, Portugal. ; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Renata Soares
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Ana V Coelho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Cecília Leão
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga 4710-057, Portugal. ; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga 4710-057, Portugal. ; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
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Identification of NDUFAF1 in mediating K-Ras induced mitochondrial dysfunction by a proteomic screening approach. Oncotarget 2016; 6:3947-62. [PMID: 25714130 PMCID: PMC4414165 DOI: 10.18632/oncotarget.2968] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 12/17/2014] [Indexed: 01/17/2023] Open
Abstract
Increase in aerobic glycolysis and mitochondrial dysfunction are important biochemical features observed in human cancers. Recent studies suggest oncogenic K-Ras can cause suppression of mitochondrial respiration and up-regulation of glycolytic activity through a yet unknown mechanism. Here we employed proteomic approach and used a K-RasG12V inducible cell system to investigate the impact of oncogenic K-Ras on mitochondria and cell metabolism. Mitochondria isolated from cells before and after K-Ras induction were subjected to protein analysis using stable isotope labeling with amino acids (SILAC) and liquid chromatography coupled with mass spectrometry (LC-MS). 70 mitochondrial proteins with significant expression alteration after K-Ras induction were identified. A majority of these proteins were involved in energy metabolism. Five proteins with significant decrease belong to mitochondrial respiratory chain complex I. NADH dehydrogenase 1 alpha subcomplex assembly factor 1 (NDUFAF1) showed most significant decrease by 50%. Such decrease was validated in primary human pancreatic cancer tissues. Knockdown of NDUFAF1 by siRNA caused mitochondrial respiration deficiency, accumulation of NADH and subsequent increase of glycolytic activity. Our study revealed that oncogenic K-Ras is able to induce significant alterations in mitochondrial protein expression, and identified NDUFAF1 as an important molecule whose low expression contributes to mitochondrial dysfunction induced by K-Ras.
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Proteomic analysis reveals a novel function of the kinase Sat4p in Saccharomyces cerevisiae mitochondria. PLoS One 2014; 9:e103956. [PMID: 25117470 PMCID: PMC4138037 DOI: 10.1371/journal.pone.0103956] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/03/2014] [Indexed: 12/24/2022] Open
Abstract
The Saccharomyces cerevisiae kinase Sat4p has been originally identified as a protein involved in salt tolerance and stabilization of plasma membrane transporters, implicating a cytoplasmic localization. Our study revealed an additional mitochondrial (mt) localization, suggesting a dual function for Sat4p. While no mt related phenotype was observed in the absence of Sat4p, its overexpression resulted in significant changes of a specific mitochondrial subproteome. As shown by a comparative two dimensional difference gel electrophoresis (2D-DIGE) approach combined with mass spectrometry, particularly two groups of proteins were affected: the iron-sulfur containing aconitase-type proteins (Aco1p, Lys4p) and the lipoamide-containing subproteome (Lat1p, Kgd2p and Gcv3p). The lipoylation sites of all three proteins could be assigned by nanoLC-MS/MS to Lys75 (Lat1p), Lys114 (Kgd2p) and Lys102 (Gcv3p), respectively. Sat4p overexpression resulted in accumulation of the delipoylated protein variants and in reduced levels of aconitase-type proteins, accompanied by a decrease in the activities of the respective enzyme complexes. We propose a regulatory role of Sat4p in the late steps of the maturation of a specific subset of mitochondrial iron-sulfur cluster proteins, including Aco1p and lipoate synthase Lip5p. Impairment of the latter enzyme may account for the observed lipoylation defects.
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7
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Crestani J, Carvalho PC, Han X, Seixas A, Broetto L, Fischer JDSDG, Staats CC, Schrank A, Yates JR, Vainstein MH. Proteomic profiling of the influence of iron availability on Cryptococcus gattii. J Proteome Res 2011; 11:189-205. [PMID: 21970549 DOI: 10.1021/pr2005296] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Iron is essential and ubiquitous in living organisms. The competition for this micronutrient between the host and its pathogens has been related to disease establishment. Cryptococcus gattii is an encapsulated yeast that causes cryptococcosis mainly in immunocompetent individuals. In this study, we analyzed the proteomic profile of the C. gattii R265 Vancouver Island isolate under iron-depleted and -repleted conditions by multidimensional protein identification technology (MudPIT) and by 2D-GE. Proteins and key mechanisms affected by alteration of iron levels such as capsule production, cAMP-signaling pathway, response to stress, and metabolic pathways related to mitochondrial function were identified. Our results also show both proteomic methodologies employed to be complementary.
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Affiliation(s)
- Juliana Crestani
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 43421, Caixa Postal 15005, Porto Alegre, RS 91501-970, Brazil
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8
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Qian X, Gebert M, Höpker J, Yan M, Li J, Wiedemann N, van der Laan M, Pfanner N, Sha B. Structural basis for the function of Tim50 in the mitochondrial presequence translocase. J Mol Biol 2011; 411:513-9. [PMID: 21704637 DOI: 10.1016/j.jmb.2011.06.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Revised: 06/13/2011] [Accepted: 06/13/2011] [Indexed: 10/18/2022]
Abstract
Many mitochondrial proteins are synthesized as preproteins carrying amino-terminal presequences in the cytosol. The preproteins are imported by the translocase of the outer mitochondrial membrane and the presequence translocase of the inner membrane. Tim50 and Tim23 transfer preproteins through the intermembrane space to the inner membrane. We report the crystal structure of the intermembrane space domain of yeast Tim50 to 1.83 Å resolution. A protruding β-hairpin of Tim50 is crucial for interaction with Tim23, providing a molecular basis for the cooperation of Tim50 and Tim23 in preprotein translocation to the protein-conducting channel of the mitochondrial inner membrane.
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Affiliation(s)
- Xinguo Qian
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Boulevard, Birmingham, AL 35294-0005, USA
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Staunton L, O'Connell K, Ohlendieck K. Proteomic Profiling of Mitochondrial Enzymes during Skeletal Muscle Aging. J Aging Res 2011; 2011:908035. [PMID: 21437005 PMCID: PMC3062155 DOI: 10.4061/2011/908035] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/17/2010] [Accepted: 01/03/2011] [Indexed: 11/20/2022] Open
Abstract
Mitochondria are of central importance for energy generation in skeletal muscles. Expression changes or functional alterations in mitochondrial enzymes play a key role during myogenesis, fibre maturation, and various neuromuscular pathologies, as well as natural fibre aging. Mass spectrometry-based proteomics suggests itself as a convenient large-scale and high-throughput approach to catalogue the mitochondrial protein complement and determine global changes during health and disease. This paper gives a brief overview of the relatively new field of mitochondrial proteomics and discusses the findings from recent proteomic surveys of mitochondrial elements in aged skeletal muscles. Changes in the abundance, biochemical activity, subcellular localization, and/or posttranslational modifications in key mitochondrial enzymes might be useful as novel biomarkers of aging. In the long term, this may advance diagnostic procedures, improve the monitoring of disease progression, help in the testing of side effects due to new drug regimes, and enhance our molecular understanding of age-related muscle degeneration.
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Affiliation(s)
- Lisa Staunton
- Department of Biology, National University of Ireland, Maynooth, County Kildare, Ireland
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Carrie C, Murcha MW, Whelan J. An in silico analysis of the mitochondrial protein import apparatus of plants. BMC PLANT BIOLOGY 2010; 10:249. [PMID: 21078193 PMCID: PMC3095331 DOI: 10.1186/1471-2229-10-249] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 11/16/2010] [Indexed: 05/04/2023]
Abstract
BACKGROUND An in silico analysis of the mitochondrial protein import apparatus from a variety of species; including Chlamydomonas reinhardtii, Chlorella variabilis, Ectocarpus siliculosus, Cyanidioschyzon merolae, Physcomitrella patens, Selaginella moellendorffii, Picea glauca, Oryza sativa and Arabidopsis thaliana was undertaken to determine if components differed within and between plant and non-plant species. RESULTS The channel forming subunits of the outer membrane components Tom40 and Sam50 are conserved between plant groups and other eukaryotes. In contrast, the receptor component(s) in green plants, particularly Tom20, (C. reinhardtii, C. variabilis, P. patens, S. moellendorffii, P. glauca, O. sativa and A. thaliana) are specific to this lineage. Red algae contain a Tom22 receptor that is orthologous to yeast Tom22. Furthermore, plant mitochondrial receptors display differences between various plant lineages. These are evidenced by distinctive motifs in all plant Metaxins, which are absent in red algae, and the presence of the outer membrane receptor OM64 in Angiosperms (rice and Arabidopsis), but not in lycophytes (S. moellendorffii) and gymnosperms (P. glauca). Furthermore, although the intermembrane space receptor Mia40 is conserved across a wide phylogenetic range, its function differs between lineages. In all plant lineages, Tim17 contains a C-terminal extension, which may act as a receptor component for the import of nucleic acids into plant mitochondria. CONCLUSIONS It is proposed that the observed functional divergences are due to the selective pressure to sort proteins between mitochondria and chloroplasts, resulting in differences in protein receptor components between plant groups and other organisms. Additionally, diversity of receptor components is observed within the plant kingdom. Even when receptor components are orthologous across plant and non-plant species, it appears that the functions of these have expanded or diverged in a lineage specific manner.
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Affiliation(s)
- Chris Carrie
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling, Crawley 6009, WA, Australia
| | - Monika W Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling, Crawley 6009, WA, Australia
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling, Crawley 6009, WA, Australia
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Abstract
Although the origin of mitochondria from the endosymbiosis of an α-proteobacterium is well established, the nature of the host cell, the metabolic complexity of the endosymbiont and the subsequent evolution of the proto-mitochondrion into all its current appearances are still the subject of discovery and sometimes debate. Here we review what has been inferred about the original composition and subsequent evolution of the mitochondrial proteome and essential mitochondrial systems. The evolutionary mosaic that currently constitutes mitochondrial proteomes contains (i) endosymbiotic proteins (15-45%), (ii) proteins without detectable orthologs outside the eukaryotic lineage (40%), and (iii) proteins that are derived from non-proteobacterial Bacteria, Bacteriophages and Archaea (15%, specifically multiple tRNA-modification proteins). Protein complexes are of endosymbiotic origin, but have greatly expanded with novel eukaryotic proteins; in contrast to mitochondrial enzymes that are both of proteobacterial and non-proteobacterial origin. This disparity is consistent with the complexity hypothesis, which argues that proteins that are a part of large, multi-subunit complexes are unlikely to undergo horizontal gene transfer. We observe that they neither change their subcellular compartments in the course of evolution, even when their genes do.
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Affiliation(s)
- Radek Szklarczyk
- Radboud University Nijmegen Medical Centre, CMBI/NCMLS, Nijmegen, The Netherlands
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12
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Mazunin IO, Volodko NV, Starikovskaya EB, Sukernik RI. Mitochondrial genome and human mitochondrial diseases. Mol Biol 2010. [DOI: 10.1134/s0026893310050018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Translocation of Porphyromonas gingivalis gingipain adhesin peptide A44 to host mitochondria prevents apoptosis. Infect Immun 2010; 78:3616-24. [PMID: 20547744 DOI: 10.1128/iai.00187-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porphyromonas gingivalis, a Gram-negative oral anaerobe, is associated with periodontal diseases that, in some form, affect up to 80% of the U.S. population. The organism is highly proteolytic, and noncatalytic adhesin domains of the major proteases, gingipains, are involved in bacterium-host interactions. Recently, we showed that gingipain adhesin peptide A44 hijacks the host's clathrin-dependent endocytosis system, allowing the peptide and whole bacteria to be internalized by epithelial cells. In the present study, we found by cell fractionation assays and confocal microscopy that peptide A44 translocated to host mitochondria. Cell viability assays and quantitative real-time PCR showed that the peptide interacted with the cell death machinery by triggering upregulation of antiapoptotic factors bcl-2 and bcl-XL and prevented staurosporine-induced apoptosis for up to 12 h. We confirmed these findings with Western blot analyses of caspase-9 activation in time course experiments with staurosporine. Finally, we verified a similar antiapoptotic effect for P. gingivalis, showing for the first time that the organism manipulated mitochondrial functions during the first hours of infection, thus resisting host cell clearance by apoptosis of infected cells. This mechanism may enable the bacteria to persist in the protected cellular environment until the next step in pathogenesis, progression or resolution of infection.
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14
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Kulkarni R, Marples B, Balasubramaniam M, Thomas RA, Tucker JD. Mitochondrial gene expression changes in normal and mitochondrial mutant cells after exposure to ionizing radiation. Radiat Res 2010; 173:635-44. [PMID: 20426663 DOI: 10.1667/rr1737.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Mitochondrial DNA (mtDNA) contains 13 genes that encode proteins of the oxidative phosphorylation complex that are involved in ATP generation. Leber's optic atrophy and Leigh's syndrome are diseases that are caused by point mutations in the mitochondrial genome and that have phenotypes associated with energy deprivation. We hypothesized that energy deficiency from mitochondrial mutations in these cells leads to radiation hypersensitivity. Here we compared mitochondrial gene expression for the 13 mitochondrial protein-coding genes in two mitochondrial mutant cell lines, GM13740 (Leigh's syndrome) and GM10744 (Leber's optic atrophy) and a normal human lymphoblastoid cell line (GM15036) after X irradiation (0-4 Gy) 0 to 24 h postirradiation. Changes in gene expression were compared with cellular radiosensitivity. Statistically significant differences between Leigh's syndrome and normal cells were found in mitochondrial gene expression for all radiation doses and times that were commensurate with changes in radiation sensitivity. The data suggest that Leigh's syndrome cells have an impaired ability to repair radiation-induced DNA damage that results in radiation hypersensitivity. This may be attributable to mitochondrial dysfunction from reductions in mitochondrial gene expression and ATP generation, since Leigh's optic atrophy cells exhibit a mutation in the ATPase6 gene, which is an important component of Complex V of ATP synthase. In contrast, the mutation of the Leber's cells conferred radioresistance, which might be attributed to the mutation in the ND4 gene in the mitochondrial genome. The altered sensitivity of mitochondrial mutant cells to ionizing radiation can lead to decreased DNA repair, which may put individuals with mtDNA mutations at greater risk for cancer and other diseases.
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Affiliation(s)
- Rohan Kulkarni
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, USA
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15
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O'Connell K, Ohlendieck K. Proteomic DIGE analysis of the mitochondria-enriched fraction from aged rat skeletal muscle. Proteomics 2010; 9:5509-24. [PMID: 19834913 DOI: 10.1002/pmic.200900472] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Skeletal muscle aging is associated with a loss in tissue mass and contractile strength, as well as fiber type shifting and bioenergetic adaptation processes. Since mitochondria represent the primary site for energy generation via oxidative phosphorylation, we investigated potential changes in the expression pattern of the mitochondrial proteome using the highly sensitive DIGE approach. The comparative analysis of the mitochondria-enriched fraction from young adult versus aged muscle revealed an age-related change in abundance for 39 protein species. MS technology identified the majority of altered proteins as constituents of muscle mitochondria. An age-dependent increase was observed for NADH dehydrogenase, the mitochondrial inner membrane protein mitofilin, peroxiredoxin isoform PRX-III, ATPase synthase, succinate dehydrogenase, mitochondrial fission protein Fis1, succinate-coenzyme A ligase, acyl-coenzyme A dehydrogenase, porin isoform VDAC2, ubiquinol-cytochrome c reductase core I protein and prohibitin. Immunoblotting, enzyme testing and confocal microscopy were used to validate proteomic findings. The DIGE-identified increase in key mitochondrial elements during aging agrees with the concept that sarcopenia is associated with a shift to a slower contractile phenotype and more pronounced aerobic-oxidative metabolism. This suggests that mitochondrial markers are reliable candidates that should be included in the future establishment of a biomarker signature of skeletal muscle aging.
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Affiliation(s)
- Kathleen O'Connell
- Department of Biology, National University of Ireland, Maynooth, Co. Kildare, Ireland
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The mitochondrial genome of the phytopathogenic basidiomycete Moniliophthora perniciosa is 109kb in size and contains a stable integrated plasmid. ACTA ACUST UNITED AC 2008; 112:1136-52. [DOI: 10.1016/j.mycres.2008.04.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 03/19/2008] [Accepted: 04/24/2008] [Indexed: 11/17/2022]
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