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[PMID]:28575662
[Au] Autor:Puri N; Karzai AW
[Ad] Endereço:Department of Biochemistry and Cell Biology, Center for Infectious Diseases, Graduate Program in Molecular and Cellular Biology, Stony Brook University, Stony Brook, NY 11794, USA.
[Ti] Título:HspQ Functions as a Unique Specificity-Enhancing Factor for the AAA+ Lon Protease.
[So] Source:Mol Cell;66(5):672-683.e4, 2017 Jun 01.
[Is] ISSN:1097-4164
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The AAA+ Lon protease is conserved from bacteria to humans, performs crucial roles in protein homeostasis, and is implicated in bacterial pathogenesis and human disease. We investigated how Lon selectively degrades specific substrates among a diverse array of potential targets. We report the discovery of HspQ as a new Lon substrate, unique specificity-enhancing factor, and potent allosteric activator. Lon recognizes HspQ via a C-terminal degron, whose precise presentation, in synergy with multipartite contacts with the native core of HspQ, is required for allosteric Lon activation. Productive HspQ-Lon engagement enhances degradation of multiple new and known Lon substrates. Our studies reveal the existence and simultaneous utilization of two distinct substrate recognition sites on Lon, an HspQ binding site and an HspQ-modulated allosteric site. Our investigations unveil an unprecedented regulatory use of an evolutionarily conserved heat shock protein and present a distinctive mechanism for how Lon protease achieves temporally enhanced substrate selectivity.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Proteínas de Choque Térmico/metabolismo
Protease La/metabolismo
Yersinia pestis/enzimologia
[Mh] Termos MeSH secundário: Regulação Alostérica
Proteínas de Bactérias/genética
Sítios de Ligação
Proteínas de Choque Térmico/genética
Cinética
Protease La/genética
Ligação Proteica
Dobramento de Proteína
Proteólise
Especificidade por Substrato
Yersinia pestis/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Heat-Shock Proteins); EC 3.4.21.53 (Protease La)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170919
[Lr] Data última revisão:
170919
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170603
[St] Status:MEDLINE


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[PMID]:28387563
[Au] Autor:Gounden S; Chuturgoon A
[Ad] Endereço:Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, Howard College, University of KwaZulu-Natal , Durban, South Africa .
[Ti] Título:Curcumin Upregulates Antioxidant Defense, Lon Protease, and Heat-Shock Protein 70 Under Hyperglycemic Conditions in Human Hepatoma Cells.
[So] Source:J Med Food;20(5):465-473, 2017 May.
[Is] ISSN:1557-7600
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Sirtuin 3 (SIRT3) regulates mitochondrial antioxidant (AO) defense and improves mitochondrial disorders. Curcumin protects mitochondria; however, the mechanisms need investigation. We postulated that curcumin increases AO defense under hyperglycemic conditions in HepG2 cells through SIRT3-mediated mechanisms. Cell viability was determined in HepG2 cells cultured with 5 mM glucose, 19.9 mM mannitol, vehicle control, 10 mM glucose, and 30 mM glucose in the absence or presence of curcumin for 24 h. SIRT3, nuclear factor-kappa B (NF-κB), heat-shock protein 70 (Hsp70), and Lon protein expressions were determined using western blot. Transcript levels of SIRT3, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), cAMP response element-binding protein (CREB), glutathione peroxidase 1 (GPx1), and superoxide dismutase 2 (SOD2) were measured by quantitative polymerase chain reaction. Cell viability, SIRT3 protein expression, transcript levels of SIRT3, PGC-1α, CREB, GPx1, and SOD2 and protein expressions of NF-κB, Lon, and Hsp70 were significantly increased in the curcumin-treated hyperglycemic groups. Since curcumin and SIRT3 both improve mitochondrial function and AO defense, SIRT3 may be involved in the protective effects of curcumin.
[Mh] Termos MeSH primário: Antioxidantes/metabolismo
Carcinoma Hepatocelular/metabolismo
Curcumina/farmacologia
Proteínas de Choque Térmico HSP70/metabolismo
Neoplasias Hepáticas/metabolismo
Protease La/metabolismo
[Mh] Termos MeSH secundário: Carcinoma Hepatocelular/enzimologia
Carcinoma Hepatocelular/genética
Linhagem Celular Tumoral
Glutationa Peroxidase/genética
Glutationa Peroxidase/metabolismo
Proteínas de Choque Térmico HSP70/genética
Seres Humanos
Neoplasias Hepáticas/enzimologia
Neoplasias Hepáticas/genética
Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética
Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo
Protease La/genética
Sirtuína 3/genética
Sirtuína 3/metabolismo
Superóxido Dismutase/genética
Superóxido Dismutase/metabolismo
Regulação para Cima
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antioxidants); 0 (HSP70 Heat-Shock Proteins); 0 (PPARGC1A protein, human); 0 (Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha); EC 1.11.1.- (glutathione peroxidase GPX1); EC 1.11.1.9 (Glutathione Peroxidase); EC 1.15.1.1 (Superoxide Dismutase); EC 1.15.1.1 (superoxide dismutase 2); EC 3.4.21.53 (Protease La); EC 3.5.1.- (SIRT3 protein, human); EC 3.5.1.- (Sirtuin 3); IT942ZTH98 (Curcumin)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170822
[Lr] Data última revisão:
170822
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170408
[St] Status:MEDLINE
[do] DOI:10.1089/jmf.2016.0146


  3 / 450 MEDLINE  
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[PMID]:28335002
[Au] Autor:Bury K; Wegrzyn K; Konieczny I
[Ad] Endereço:Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-308 Gdansk, Poland.
[Ti] Título:Handcuffing reversal is facilitated by proteases and replication initiator monomers.
[So] Source:Nucleic Acids Res;45(7):3953-3966, 2017 Apr 20.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Specific nucleoprotein complexes are formed strictly to prevent over-initiation of DNA replication. An example of those is the so-called handcuff complex, in which two plasmid molecules are coupled together with plasmid-encoded replication initiation protein (Rep). In this work, we elucidate the mechanism of the handcuff complex disruption. In vitro tests, including dissociation progress analysis, demonstrate that the dimeric variants of plasmid RK2 replication initiation protein TrfA are involved in assembling the plasmid handcuff complex which, as we found, reveals high stability. Particular proteases, namely Lon and ClpAP, disrupt the handcuff by degrading TrfA, thus affecting plasmid stability. Moreover, our data demonstrate that TrfA monomers are able to dissociate handcuffed plasmid molecules. Those monomers displace TrfA molecules, which are involved in handcuff formation, and through interaction with the uncoupled plasmid replication origins they re-initiate DNA synthesis. We discuss the relevance of both Rep monomers and host proteases for plasmid maintenance under vegetative and stress conditions.
[Mh] Termos MeSH primário: Replicação do DNA
Endopeptidase Clp/metabolismo
Proteínas de Escherichia coli/metabolismo
Plasmídeos/biossíntese
Protease La/metabolismo
[Mh] Termos MeSH secundário: DNA Bacteriano/biossíntese
Escherichia coli/enzimologia
Escherichia coli/genética
Escherichia coli/metabolismo
Proteínas de Escherichia coli/genética
Nucleoproteínas/metabolismo
Plasmídeos/metabolismo
Protease La/genética
Multimerização Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (DNA, Bacterial); 0 (Escherichia coli Proteins); 0 (Nucleoproteins); 0 (TrfA protein, E coli); EC 3.4.21.53 (ClpA protease, E coli); EC 3.4.21.53 (Lon protein, E coli); EC 3.4.21.53 (Protease La); EC 3.4.21.92 (ClpP protease, E coli); EC 3.4.21.92 (Endopeptidase Clp)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171005
[Lr] Data última revisão:
171005
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170324
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx166


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[PMID]:28292931
[Au] Autor:Karlowicz A; Wegrzyn K; Gross M; Kaczynska D; Ropelewska M; Siemiatkowska M; Bujnicki JM; Konieczny I
[Ad] Endereço:From the Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland.
[Ti] Título:Defining the crucial domain and amino acid residues in bacterial Lon protease for DNA binding and processing of DNA-interacting substrates.
[So] Source:J Biol Chem;292(18):7507-7518, 2017 May 05.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Lon protease previously has been shown to interact with DNA, but the role of this interaction for Lon proteolytic activity has not been characterized. In this study, we used truncated Lon constructs, bioinformatics analysis, and site-directed mutagenesis to identify Lon domains and residues crucial for Lon binding with DNA and effects on Lon proteolytic activity. We found that deletion of Lon's ATPase domain abrogated interactions with DNA. Substitution of positively charged amino acids in this domain in full-length Lon with residues conferring a net negative charge disrupted binding of Lon to DNA. These changes also affected the degradation of nucleic acid-binding protein substrates of Lon, intracellular localization of Lon, and cell morphology. tests revealed that Lon-DNA interactions are essential for Lon activity in cell division control. In summary, we demonstrate that the ability of Lon to bind DNA is determined by its ATPase domain, that this binding is required for processing protein substrates in nucleoprotein complexes, and that Lon may help regulate DNA replication in response to growth conditions.
[Mh] Termos MeSH primário: Adenosina Trifosfatases/metabolismo
Replicação do DNA/fisiologia
DNA Bacteriano/biossíntese
Proteínas de Ligação a DNA/metabolismo
Proteínas de Escherichia coli/metabolismo
Escherichia coli/enzimologia
Protease La/metabolismo
[Mh] Termos MeSH secundário: Adenosina Trifosfatases/genética
Divisão Celular/fisiologia
DNA Bacteriano/genética
Proteínas de Ligação a DNA/genética
Escherichia coli/genética
Proteínas de Escherichia coli/genética
Protease La/genética
Domínios Proteicos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (DNA, Bacterial); 0 (DNA-Binding Proteins); 0 (Escherichia coli Proteins); EC 3.4.21.53 (Lon protein, E coli); EC 3.4.21.53 (Protease La); EC 3.6.1.- (Adenosine Triphosphatases)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170607
[Lr] Data última revisão:
170607
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170316
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M116.766709


  5 / 450 MEDLINE  
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[PMID]:27856638
[Au] Autor:Crewe C; Schafer C; Lee I; Kinter M; Szweda LI
[Ad] Endereço:From the Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104.
[Ti] Título:Regulation of Pyruvate Dehydrogenase Kinase 4 in the Heart through Degradation by the Lon Protease in Response to Mitochondrial Substrate Availability.
[So] Source:J Biol Chem;292(1):305-312, 2017 Jan 06.
[Is] ISSN:1083-351X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Cardiac metabolic inflexibility is driven by robust up-regulation of pyruvate dehydrogenase kinase 4 (PDK4) and phosphorylation-dependent inhibition of pyruvate dehydrogenase (PDH) within a single day of feeding mice a high fat diet. In the current study, we have discovered that PDK4 is a short lived protein (t ∼ 1 h) and is specifically degraded by the mitochondrial protease Lon. Lon does not rapidly degrade PDK1 and -2, indicating specificity toward the PDK isoform that is a potent modulator of metabolic flexibility. Moreover, PDK4 degradation appears regulated by dissociation from the PDH complex dependent on the respiratory state and energetic substrate availability of mouse heart mitochondria. Finally, we demonstrate that pharmacologic inhibition of PDK4 promotes PDK4 degradation in vitro and in vivo These findings reveal a novel strategy to manipulate PDH activity by selectively targeting PDK4 content through dissociation and proteolysis.
[Mh] Termos MeSH primário: Regulação Enzimológica da Expressão Gênica
Mitocôndrias Cardíacas/metabolismo
Miócitos Cardíacos/metabolismo
Protease La/metabolismo
Proteínas Serina-Treonina Quinases/metabolismo
Complexo Piruvato Desidrogenase/metabolismo
[Mh] Termos MeSH secundário: Animais
Células Cultivadas
Masculino
Camundongos
Camundongos Endogâmicos C57BL
Miócitos Cardíacos/citologia
Fosforilação
Protease La/genética
Proteínas Serina-Treonina Quinases/genética
Complexo Piruvato Desidrogenase/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Pyruvate Dehydrogenase Complex); EC 2.7.11.1 (Protein-Serine-Threonine Kinases); EC 2.7.11.2 (pyruvate dehydrogenase (acetyl-transferring) kinase); EC 3.4.21.53 (Protease La)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170602
[Lr] Data última revisão:
170602
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161119
[St] Status:MEDLINE
[do] DOI:10.1074/jbc.M116.754127


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[PMID]:27543838
[Au] Autor:Vass RH; Zeinert RD; Chien P
[Ad] Endereço:Department of Biochemistry and Molecular Biology, Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, USA.
[Ti] Título:Protease regulation and capacity during Caulobacter growth.
[So] Source:Curr Opin Microbiol;34:75-81, 2016 Dec.
[Is] ISSN:1879-0364
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Cell growth requires the removal of proteins that are unwanted or toxic. In bacteria, AAA+ proteases like the Clp family and Lon selectively destroy proteins defined by intrinsic specificity or adaptors. Caulobacter crescentus is a gram-negative bacterium that undergoes an obligate developmental transition every cell division cycle. Here we highlight recent work that reveals how a hierarchy of adaptors targets the degradation of key proteins at specific times during this cell cycle, integrating protein destruction with other cues. We describe recent insight into how Caulobacter manages DNA replication and repair through Lon and Clp proteases. Because proteases must manage a broad substrate repertoire there must be methods to compensate for protease saturation and we discuss these scenarios.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Caulobacter crescentus/enzimologia
Caulobacter crescentus/crescimento & desenvolvimento
Peptídeo Hidrolases/genética
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Caulobacter crescentus/genética
Ciclo Celular/genética
Divisão Celular
Replicação do DNA/genética
DNA Bacteriano
Endopeptidase Clp/genética
Endopeptidase Clp/metabolismo
Regulação Bacteriana da Expressão Gênica
Peptídeo Hidrolases/metabolismo
Protease La/genética
Protease La/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (DNA, Bacterial); EC 3.4.- (Peptide Hydrolases); EC 3.4.21.53 (Protease La); EC 3.4.21.92 (Endopeptidase Clp)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171106
[Lr] Data última revisão:
171106
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160821
[St] Status:MEDLINE


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[PMID]:27531906
[Au] Autor:Strugeon E; Tilloy V; Ploy MC; Da Re S
[Ad] Endereço:Inserm, UMR1092, Université de Limoges, UMR-S1092, and CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, Limoges, France.
[Ti] Título:The Stringent Response Promotes Antibiotic Resistance Dissemination by Regulating Integron Integrase Expression in Biofilms.
[So] Source:MBio;7(4), 2016 Aug 16.
[Is] ISSN:2150-7511
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:UNLABELLED: Class 1 integrons are genetic systems that enable bacteria to capture and express gene cassettes. These integrons, when isolated in clinical contexts, most often carry antibiotic resistance gene cassettes. They play a major role in the dissemination of antibiotic resistance among Gram-negative bacteria. The key element of integrons is the integrase, which allows gene cassettes to be acquired and shuffled. Planktonic culture experiments have shown that integrase expression is regulated by the bacterial SOS response. In natural settings, however, bacteria generally live in biofilms, which are characterized by strong antibiotic resilience and by increased expression of stress-related genes. Here, we report that under biofilm conditions, the stringent response, which is induced upon starvation, (i) increases basal integrase and SOS regulon gene expression via induction of the SOS response and (ii) exerts biofilm-specific regulation of the integrase via the Lon protease. This indicates that biofilm environments favor integron-mediated acquisition of antibiotic resistance and other adaptive functions encoded by gene cassettes. IMPORTANCE: Multidrug-resistant bacteria are becoming a worldwide health problem. Integrons are bacterial genetic platforms that allow the bacteria to capture and express gene cassettes. In clinical settings, integrons play a major role in the dissemination of antibiotic resistance gene cassettes among Gram-negative bacteria. Cassette capture is catalyzed by the integron integrase, whose expression is induced by DNA damage and controlled by the bacterial SOS response in laboratory planktonic cultures. In natural settings, bacteria usually grow in heterogeneous environments known as biofilms, which have very different conditions than planktonic cultures. Integrase regulation has not been investigated in biofilms. Our results showed that in addition to the SOS response, the stringent response (induced upon starvation) is specifically involved in the regulation of class 1 integron integrases in biofilms. This study shows that biofilms are favorable environments for integron-mediated acquisition/exchange of antibiotic resistance genes by bacteria and for the emergence of multidrug-resistant bacteria.
[Mh] Termos MeSH primário: Biofilmes/crescimento & desenvolvimento
Farmacorresistência Bacteriana
Escherichia coli/fisiologia
Regulação Bacteriana da Expressão Gênica
Expressão Gênica
Integrases/biossíntese
Integrons
[Mh] Termos MeSH secundário: Escherichia coli/genética
Protease La/metabolismo
Resposta SOS (Genética)
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
EC 2.7.7.- (Integrases); EC 3.4.21.53 (Protease La)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170620
[Lr] Data última revisão:
170620
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160818
[St] Status:MEDLINE


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[PMID]:27392670
[Au] Autor:Bonet-Costa V; Pomatto LC; Davies KJ
[Ad] Endereço:Leonard Davis School of Gerontology, Ethel Percy Andrus Gerontology Center, The Division of Molecular and Computational Biology, Department of Biological Sciences, Dornsife College of Letters, Arts, and Sciences, The University of Southern California , Los Angeles, California.
[Ti] Título:The Proteasome and Oxidative Stress in Alzheimer's Disease.
[So] Source:Antioxid Redox Signal;25(16):886-901, 2016 Dec 01.
[Is] ISSN:1557-7716
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:SIGNIFICANCE: Alzheimer's disease is a neurodegenerative disorder that is projected to exceed more than 100 million cases worldwide by 2050. Aging is considered the primary risk factor for some 90% of Alzheimer's cases but a significant 10% of patients suffer from aggressive, early-onset forms of the disease. There is currently no effective Alzheimer's treatment and this, coupled with a growing aging population, highlights the necessity to understand the mechanism(s) of disease initiation and propagation. A major hallmark of Alzheimer's disease pathology is the accumulation of amyloid-ß (Aß) aggregates (an early marker of Alzheimer's disease), and neurofibrillary tangles, comprising the hyper-phosphorylated microtubule-associated protein Tau. Recent Advances: Protein oxidation is frequently invoked as a potential factor in the progression of Alzheimer's disease; however, whether it is a cause or a consequence of the pathology is still being debated. The Proteasome complex is a major regulator of intracellular protein quality control and an essential proteolytic enzyme for the processing of both Aß and Tau. Recent studies have indicated that both protein oxidation and excessive phosphorylation may limit Proteasomal processing of Aß and Tau in Alzheimer's disease. CRITICAL ISSUES: Thus, the Proteasome may be a key factor in understanding the development of Alzheimer's disease pathology; however, its significance is still very much under investigation. FUTURE DIRECTIONS: Discovering how the proteasome is affected, regulated, or dysregulated in Alzheimer's disease could be a valuable tool in the efforts to understand and, ultimately, eradicate the disease. Antioxid. Redox Signal. 25, 886-901.
[Mh] Termos MeSH primário: Doença de Alzheimer/etiologia
Doença de Alzheimer/metabolismo
Estresse Oxidativo
Complexo de Endopeptidases do Proteassoma/metabolismo
[Mh] Termos MeSH secundário: Envelhecimento/metabolismo
Peptídeos beta-Amiloides/metabolismo
Animais
Seres Humanos
Mitocôndrias/metabolismo
Oxirredução
Fosforilação
Protease La/metabolismo
Proteólise
Proteínas tau/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Amyloid beta-Peptides); 0 (tau Proteins); EC 3.4.21.53 (Protease La); EC 3.4.25.1 (Proteasome Endopeptidase Complex)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170807
[Lr] Data última revisão:
170807
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160710
[St] Status:MEDLINE


  9 / 450 MEDLINE  
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[PMID]:27252455
[Au] Autor:Ivanina AV; Nesmelova I; Leamy L; Sokolov EP; Sokolova IM
[Ad] Endereço:Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
[Ti] Título:Intermittent hypoxia leads to functional reorganization of mitochondria and affects cellular bioenergetics in marine molluscs.
[So] Source:J Exp Biol;219(Pt 11):1659-74, 2016 Jun 01.
[Is] ISSN:1477-9145
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Fluctuations in oxygen (O2) concentrations represent a major challenge to aerobic organisms and can be extremely damaging to their mitochondria. Marine intertidal molluscs are well-adapted to frequent O2 fluctuations, yet it remains unknown how their mitochondrial functions are regulated to sustain energy metabolism and prevent cellular damage during hypoxia and reoxygenation (H/R). We used metabolic control analysis to investigate the mechanisms of mitochondrial responses to H/R stress (18 h at <0.1% O2 followed by 1 h of reoxygenation) using hypoxia-tolerant intertidal clams Mercenaria mercenaria and hypoxia-sensitive subtidal scallops Argopecten irradians as models. We also assessed H/R-induced changes in cellular energy balance, oxidative damage and unfolded protein response to determine the potential links between mitochondrial dysfunction and cellular injury. Mitochondrial responses to H/R in scallops strongly resembled those in other hypoxia-sensitive organisms. Exposure to hypoxia followed by reoxygenation led to a strong decrease in the substrate oxidation (SOX) and phosphorylation (PHOS) capacities as well as partial depolarization of mitochondria of scallops. Elevated mRNA expression of a reactive oxygen species-sensitive enzyme aconitase and Lon protease (responsible for degradation of oxidized mitochondrial proteins) during H/R stress was consistent with elevated levels of oxidative stress in mitochondria of scallops. In hypoxia-tolerant clams, mitochondrial SOX capacity was enhanced during hypoxia and continued rising during the first hour of reoxygenation. In both species, the mitochondrial PHOS capacity was suppressed during hypoxia, likely to prevent ATP wastage by the reverse action of FO,F1-ATPase. The PHOS capacity recovered after 1 h of reoxygenation in clams but not in scallops. Compared with scallops, clams showed a greater suppression of energy-consuming processes (such as protein turnover and ion transport) during hypoxia, indicated by inactivation of the translation initiation factor EIF-2α, suppression of 26S proteasome activity and a dramatic decrease in the activity of Na(+)/K(+)-ATPase. The steady-state levels of adenylates were preserved during H/R exposure and AMP-dependent protein kinase was not activated in either species, indicating that the H/R exposure did not lead to severe energy deficiency. Taken together, our findings suggest that mitochondrial reorganizations sustaining high oxidative phosphorylation flux during recovery, combined with the ability to suppress ATP-demanding cellular functions during hypoxia, may contribute to high resilience of clams to H/R stress and help maintain energy homeostasis during frequent H/R cycles in the intertidal zone.
[Mh] Termos MeSH primário: Organismos Aquáticos/fisiologia
Metabolismo Energético
Hipóxia/fisiopatologia
Mercenaria/fisiologia
Mitocôndrias/metabolismo
Pectinidae/fisiologia
[Mh] Termos MeSH secundário: Aconitato Hidratase/genética
Aconitato Hidratase/metabolismo
Difosfato de Adenosina/farmacologia
Aerobiose/efeitos dos fármacos
Anaerobiose/efeitos dos fármacos
Animais
Organismos Aquáticos/efeitos dos fármacos
Biomarcadores/metabolismo
Metabolismo Energético/efeitos dos fármacos
Hepatopâncreas/efeitos dos fármacos
Hepatopâncreas/fisiopatologia
Homeostase/efeitos dos fármacos
Cinética
Potencial da Membrana Mitocondrial/efeitos dos fármacos
Mercenaria/efeitos dos fármacos
Mitocôndrias/efeitos dos fármacos
Oxirredução/efeitos dos fármacos
Estresse Oxidativo/efeitos dos fármacos
Oxigênio/farmacologia
Pectinidae/efeitos dos fármacos
Fosforilação/efeitos dos fármacos
Protease La/genética
Protease La/metabolismo
Complexo de Endopeptidases do Proteassoma/metabolismo
Prótons
RNA Mensageiro/genética
RNA Mensageiro/metabolismo
Descanso/fisiologia
ATPase Trocadora de Sódio-Potássio/metabolismo
Estresse Fisiológico/efeitos dos fármacos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Biomarkers); 0 (Protons); 0 (RNA, Messenger); 61D2G4IYVH (Adenosine Diphosphate); EC 3.4.21.53 (Protease La); EC 3.4.25.1 (Proteasome Endopeptidase Complex); EC 3.6.3.9 (Sodium-Potassium-Exchanging ATPase); EC 4.2.1.3 (Aconitate Hydratase); S88TT14065 (Oxygen)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170811
[Lr] Data última revisão:
170811
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160603
[St] Status:MEDLINE
[do] DOI:10.1242/jeb.134700


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[PMID]:27239160
[Au] Autor:Pei J; Yan J; Jiang Y
[Ad] Endereço:Department of Gastroenterology, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, China.
[Ti] Título:Characterization of the ATP-Dependent Lon-Like Protease in Methanobrevibacter smithii.
[So] Source:Archaea;2016:5759765, 2016.
[Is] ISSN:1472-3654
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The Lon protease is highly evolutionarily conserved. However, little is known about Lon in the context of gut microbial communities. A gene encoding a Lon-like protease (Lon-like-Ms) was identified and characterized from Methanobrevibacter smithii, the predominant archaeon in the human gut ecosystem. Phylogenetic and sequence analyses showed that Lon-like-Ms and its homologs are newly identified members of the Lon family. A recombinant form of the enzyme was purified by affinity chromatography, and its catalytic properties were examined. Recombinant Lon-like-Ms exhibited ATPase activity and cleavage activity toward fluorogenic peptides and casein. The peptidase activity of Lon-like-Ms relied strictly on Mg(2+) (or other divalent cations) and ATP. These results highlight a new type of Lon-like protease that differs from its bacterial counterpart.
[Mh] Termos MeSH primário: Trifosfato de Adenosina/metabolismo
Methanobrevibacter/enzimologia
Methanobrevibacter/genética
Protease La/genética
Protease La/metabolismo
[Mh] Termos MeSH secundário: Adenosina Trifosfatases/metabolismo
Sequência de Aminoácidos
Cromatografia de Afinidade
Análise por Conglomerados
Coenzimas/metabolismo
DNA Arqueal/química
DNA Arqueal/genética
Microbioma Gastrointestinal
Seres Humanos
Magnésio/metabolismo
Methanobrevibacter/isolamento & purificação
Microbiota
Dados de Sequência Molecular
Filogenia
Protease La/isolamento & purificação
Análise de Sequência de DNA
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Coenzymes); 0 (DNA, Archaeal); 8L70Q75FXE (Adenosine Triphosphate); EC 3.4.21.53 (Protease La); EC 3.6.1.- (Adenosine Triphosphatases); I38ZP9992A (Magnesium)
[Em] Mês de entrada:1611
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160531
[St] Status:MEDLINE
[do] DOI:10.1155/2016/5759765



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