RESUMO
Cyclophilins contain the conserved activity of cis-trans peptidyl-prolyl isomerase that is implicated in protein folding and function as molecular chaperones. The yeast cyclophilin A gene (cpr1) was subcloned to the prokaryotic expression vector pKM260. It was found that the expression of Cpr1 drastically increased the cell viability of E. coli BL21 in the presence of abiotic stress conditions, such as cadmium, copper, hydrogen peroxide, heat, and SDS. Thus, this study illustrates the importance of Cpr1 as a molecular chaperone that improved cellular stress responses when E. coli cells were exposed to adverse conditions, and it also shows the possibility of increasing the stability of E. coli strains utilized for the production of recombinant proteins.
Assuntos
Ciclofilina A/genética , Escherichia coli/fisiologia , Expressão Gênica , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Ciclofilina A/metabolismo , Escherichia coli/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Estresse FisiológicoRESUMO
Activity-dependent local translation in the dendrites of brain neurons plays an important role in the synapse-specific provision of proteins necessary for strengthening synaptic connections. In this study we carried out combined fluorescence in situ hybridization (FISH) and immunocytochemistry (IC) and showed that more than half of the eukaryotic elongation factor 1A (eEF1A) mRNA clusters overlapped with or were immediately adjacent to clusters of PSD-95, a postsynaptic marker, in the dendrites of cultured rat hippocampal neurons. Treatment of the neurons with KCl increased the density of the dendritic eEF1A mRNA clusters more than two-fold. FISH combined with IC revealed that the KCl treatment increased the density of eEF1A mRNA clusters that overlapped with or were immediately adjacent to PSD-95 clusters. These results indicate that KCl treatment increases both the density of eEF1A mRNA clusters and their synaptic association in dendrites of cultured neurons.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Dendritos/metabolismo , Hipocampo/citologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , RNA Mensageiro/metabolismo , Animais , Transporte Biológico Ativo/efeitos dos fármacos , Transporte Biológico Ativo/genética , Células Cultivadas , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/ultraestrutura , Dendritos/genética , Proteína 4 Homóloga a Disks-Large , Hibridização in Situ Fluorescente , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Proteínas de Membrana/ultraestrutura , Microscopia Confocal , Neurônios/citologia , Neurônios/efeitos dos fármacos , Cloreto de Potássio/farmacologia , RNA Mensageiro/química , RNA Mensageiro/ultraestrutura , Ratos , Ratos Sprague-Dawley , Membranas Sinápticas/ultraestrutura , Regulação para CimaRESUMO
By combining in situ hybridization (ISH) and immunocytochemistry (IC), microscopic topological localization of mRNAs and proteins can be determined. Although this technique can be applied to a variety of tissues, it is particularly important for use on neuronal cells which are morphologically complex and in which specific mRNAs and proteins are located in distinct subcellular domains such as dendrites and dendritic spines. One common technical problem for combined ISH and IC is that the signal for immunocytochemical localization of proteins often becomes much weaker after conducting ISH. In this manuscript, we report a simplified but robust protocol that allows immunocytochemical localization of proteins after ISH. In this protocol, we fix cultured cortical or hippocampal neurons with 4% paraformaldehyde (PFA), rinse briefly in PBS, and then further fix the cells with C methanol. Our method has several major advantages over previously described ones in that (1) it is simple, as it is just consecutive routine fixation procedures, (2) it does not require any special alteration to the fixation procedures such as changes in salt concentration, and (3) it can be used with antibodies that are compatible with either methanol (MeOH-) or PFA-fixed target proteins. To our best knowledge, we are the first to employ this fixation method for fluorescence ISH + IC.
Assuntos
Imuno-Histoquímica/métodos , Hibridização in Situ Fluorescente/métodos , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Proteínas Quinases Dependentes de Cálcio-Calmodulina/análise , Células Cultivadas , Feminino , Fixadores , Hipocampo/citologia , Microscopia Confocal , Neurônios , Gravidez , Ratos , Ratos Sprague-DawleyRESUMO
The Saccharomyces cerevisiae KNU5377 strain, which was isolated from spoilage in nature, has the ability to convert biomass to alcohol at high temperatures and it can resist against various stresses. In order to understand the defense mechanisms of the KNU5377 strain under menadione (MD) as oxidative stress, we used several techniques for study: peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) followed by two-dimensional (2D) gel electrophoresis, liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), and surface-enhanced laser desorption ionization-time of flight (SELDI-TOF) technology. Among the 35 proteins identified by MALDI-TOF MS, 19 proteins including Sod1p, Sod2p, Tsa1p, and Ahp1p were induced under stress condition, while 16 proteins were augmented under normal condition. In particular, five proteins, Sod1p, Sod2p, Ahp1p, Rib3p, Yaf9p, and Mnt1p, were induced in only stressed cells. By LC-ESI-MS/MS analysis, 37 proteins were identified in normal cells and 49 proteins were confirmed in the stressed cells. Among the identified proteins, 32 proteins were found in both cells. Five proteins including Ye1047cp and Met6p were only upregulated in the normal cells, whereas 17 proteins including Abp1p and Sam1p were elevated in the stressed cells. It was interesting that highly hypothetical proteins such as Ynl281wp, Ygr279cp, Ypl273wp, Ykl133cp, and Ykr074wp were only expressed in the stressed cells. SELDI-TOF analysis using the SAX2 and WCX2 chips showed that highly multiple-specific protein patterns were reproducibly detected in ranges from 2.9 to 27.0 kDa both under normal and stress conditions. Therefore, induction of antioxidant proteins, hypothetical proteins, and low molecular weight proteins were revealed by different proteomic techniques. These results suggest that comparative analyses using proteomics might contribute to elucidate the defense mechanisms of KNU5377 under MD stress.
Assuntos
Proteínas Fúngicas/análise , Estresse Oxidativo/efeitos dos fármacos , Proteômica/métodos , Saccharomyces cerevisiae/química , Vitamina K 3/farmacologia , Sequência de Aminoácidos , Dados de Sequência Molecular , Saccharomyces cerevisiae/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
In this study, we attempted to characterize the physiological response to oxidative stress by heat shock in Saccharomyces cerevisiae KNU5377 (KNU5377) that ferments at a temperature of 40 degrees C. The KNU5377 strain evidenced a very similar growth rate at 40 degrees C as was recorded under normal conditions. Unlike the laboratory strains of S. cerevisiae, the cell viability of KNU5377 was affected slightly under 2 hours of heat stress conditions at 43 degrees C. KNU5377 evidenced a time-dependent increase in hydroperoxide levels, carbonyl contents, and malondialdehyde (MDA), which increased in the expression of a variety of cell rescue proteins containing Hsp104p, Ssap, Hsp30p, Sod1p, catalase, glutathione reductase, G6PDH, thioredoxin, thioredoxin peroxidase (Tsa1p), Adhp, Aldp, trehalose and glycogen at high temperature. Pma1/2p, Hsp90p and H+-ATPase expression levels were reduced as the result of exposure to heat shock. With regard to cellular fatty acid composition, levels of unsaturated fatty acids (USFAs) were increased significantly at high temperatures (43 degrees C), and this was particularly true of oleic acid (C18:1). The results of this study indicated that oxidative stress as the result of heat shock may induce a more profound stimulation of trehalose, antioxidant enzymes, and heat shock proteins, as well as an increase in the USFAs ratios. This might contribute to cellular protective functions for the maintenance of cellular homeostasis, and may also contribute to membrane fluidity.
Assuntos
Resposta ao Choque Térmico/fisiologia , Estresse Oxidativo/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Western Blotting , Ácidos Graxos Insaturados/metabolismo , Regulação Fúngica da Expressão Gênica/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Temperatura , Fatores de Tempo , Trealose/metabolismoRESUMO
To investigate the tolerance factor of Saccharomyces cerevisiae KNU5377 against various types of environmental stress during fermentation, we identified the protein that is upregulated at high temperatures. The highly upregulated protein was high-score-matched as a cytoplasmic peptidyl-prolyl cis-trans isomerase, cyclophilin (Cpr1p), by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). We constructed a CPR1-deleted KNU5377 strain (KNU5377Y cpr1Delta) to determine the roles of the protein under fermentative or stress condition. The growth of the S. cerevisiae KNU5377Y cpr1Delta strain was completely inhibited under the following conditions: heat (40 degrees C), hydrogen peroxide (20-30 mM), menadione (0.3 mM), ethanol (16%), sulfuric acid (5 mm), and lactic acid (0.4-0.8%). However, the wild-type and cpr1Delta mutant of S. cerevisiae BY4741 as a positive control did not show differences in sensitivity to stress. It is interesting to note that the wild-type KNU5377Y and KNU5377Y cpr1Delta mutant showed high sensitivity against various stresses, particularly, acid stress such as in the presence of sulfuric and lactic acid. Although the alcohol fermentation rate of the KNU5377Y cpr1Delta mutant markedly decreased with an increase in temperature up to 40 degrees C, we observed no decrease in that of the wild-type strain under the same conditions. These results suggest that CPR1 contributes to the stress tolerance of KNU5377 against various types of environmental stress caused during fermentation, thus leading to the physiological role of maintaining an alcohol fermentation yield, even at high temperatures such as 40 degrees C.
Assuntos
Técnicas de Cultura de Células/métodos , Etanol/metabolismo , Estresse Oxidativo/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Fermentação/fisiologia , Inativação Gênica , Saccharomyces cerevisiae/genéticaRESUMO
Autonomous ultradian metabolic oscillation (T approximately or =50 min) was detected in an aerobic chemostat culture of Saccharomyces cerevisiae. A pulse injection of GSH (a reduced form of glutathione) into the culture induced a perturbation in metabolic oscillation, with respiratory inhibition caused by H2S burst production. As the production of H2S in the culture was controlled by different amino acids, we attempted to characterize the effects of GSH on amino acid metabolism, particularly with regard to branched chain and sulfur-containing amino acids. During stable metabolic oscillation, concentrations of intracellular glutamate, aspartate, threonine, valine, leucine, isoleucine, and cysteine were observed to oscillate with the same periods of dissolved O2 oscillation, although the oscillation amplitudes and maximal phases were shown to differ. The methionine concentration was stably maintained at 0.05 mM. When GSH (100 microM) was injected into the culture, cellular levels of branched chain amino acids increased dramatically with continuous H2S production, whereas the cysteine and methionine concentrations were noticeably reduced. These results indicate that GSH-dependent perturbation occurs as the result of the promotion of branched chain amino acid synthesis and an attenuation of cysteine and methionine synthesis, both of which activate the generation of H2S. In a low sulfate medium containing 2.5 mM sulfate, the GSH injections did not result in perturbations of dissolved O2, NAD(P)H redox oscillations without burst H2 production. This suggests that GSH-dependent perturbation is intimately linked with the metabolism of branched-chain amino acids and H2 generation, rather than with direct GSH-GSSG redox control.
Assuntos
Aminoácidos de Cadeia Ramificada/metabolismo , Aminoácidos Sulfúricos/metabolismo , Saccharomyces cerevisiae/metabolismo , Relógios Biológicos/fisiologia , Reatores Biológicos/microbiologia , Glutationa/metabolismo , Sulfeto de Hidrogênio/metabolismo , Oxigênio/metabolismoRESUMO
Ubiquitin-mediated protein degradation in vertebrates has been implicated in cell cycle control. In this report we explored the effects of proteasome inhibitors (MG132, lactacystin and ALLN) on cell cycle distribution. Colorectal carcinoma HCT116 cells were treated with proteasome inhibitor MG132. The results showed that MG132 inhibited cell proliferation in a dose-dependent manner. MG132 arrested HCT116 cells at G2/M phase, which was associated with drug-induced blockade of p53 degradation and/or induction of p53-related gene expression along with the accumulation of cyclin B, cyclin A and p21. MG132 treated HCT116 (wild-type) had a similar cell cycle distribution as the MG132 treated HCT116 (p53-/-) and HCT116 (p21-/-) cells, suggesting that p53 and p21 may not be essential for MG132-induced G2/M phase arrest. The release experiments from nocodazole-induced mitotic phase cells indicated that MG132 inhibits the proliferation of HCT116 cells via arrest in the G2 phase. In addition, when HCT116 cells were exposed to combination of sodium butyrate and MG132 enhanced cell growth inhibition and induction of apoptosis were observed.
Assuntos
Acetilcisteína/análogos & derivados , Apoptose/efeitos dos fármacos , Neoplasias Colorretais/metabolismo , Ciclinas/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Fase G2/efeitos dos fármacos , Mitose/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismo , Acetilcisteína/farmacologia , Butiratos/farmacologia , Caspases/metabolismo , Divisão Celular/efeitos dos fármacos , Neoplasias Colorretais/patologia , Inibidor de Quinase Dependente de Ciclina p21 , Cisteína Endopeptidases , Quimioterapia Combinada , Humanos , Leupeptinas/farmacologia , Complexos Multienzimáticos/antagonistas & inibidores , Complexo de Endopeptidases do Proteassoma , Células Tumorais Cultivadas , Ubiquitinas/metabolismoRESUMO
The 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein of unknown function in vivo, is abundantly expressed in myelinating glia in two isoforms, CNP1 and CNP2. In this study, immunoblot analysis showed that CNP1 is the major isoform in adult forebrain, and that both isoforms are included in the postsynaptic density (PSD) fraction and tyrosine-phosphorylated at the basal level. However, subcellular distribution and detergent extraction data showed that CNP is nonspecifically associated with the PSD fraction. Immunocytochemistry revealed that CNP is detected, in a weak but punctate pattern, in dissociated rat hippocampal neurons of 3 days to 2 weeks in vitro. The CNP-positive punctae were distributed throughout soma and dendrites, and distinct from PSD95-positive ones. Immunoblot analysis indicated that CNP is also expressed in neuronal stem cell lines, HiB5 and F11. Interestingly, in addition to the known two isoforms, a new CNP isoform of MW 45 kDa was expressed in these cell lines and was the major type of isoform in F11 cells. Taken together, our data suggest that CNP is expressed in the early stage of in vitro development and nonspecifically included in the adult rat PSD fraction.
Assuntos
2',3'-Nucleotídeo Cíclico Fosfodiesterases/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Prosencéfalo/metabolismo , Envelhecimento/fisiologia , Animais , Células Cultivadas , Hipocampo/citologia , Hipocampo/metabolismo , Imuno-Histoquímica , Neurônios/metabolismo , Fosfotirosina/metabolismo , Prosencéfalo/citologia , Ratos , Ratos Sprague-Dawley , Especificidade por SubstratoRESUMO
Periodic evolution of H(2)S during aerobic chemostat culture of Saccharomyces cerevisiae resulted in ultradian metabolic oscillation via periodic inhibition of respiratory activity. To understand the nature of periodic H(2)S evolution, we investigated whether oxidative stress is associated with H(2)S production. The cellular oxidative states represented by intracellular level of lipid peroxides oscillated out of phase with the oscillation of dissolved O(2). Pulse addition of antioxidant, oxidative agent or inhibitor of antioxidation enzymes perturbed metabolic oscillation producing changes in H(2)S evolution. Analysis of H(2)S production profiles during perturbation of oscillation revealed that the amount of H(2)S production is closely linked with cellular oxidative states. Based on these results and our previous reports, we suggest that oxidative stresses result in periodic depletion of glutathione and cysteine, which in turn causes stimulation of the sulfate assimilation pathway and H(2)S production.
Assuntos
Relógios Biológicos/fisiologia , Regulação Fúngica da Expressão Gênica , Sulfeto de Hidrogênio/metabolismo , Estresse Oxidativo , Saccharomyces cerevisiae/fisiologia , Aerobiose , Glutationa/metabolismo , Oxirredução , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismoRESUMO
We have shown by protein sequencing that the phosphotyrosine-containing 48 kDa protein band of the rat cerebellar postsynaptic density fraction (CBL-PSD) is 2', 3'-cyclic nucleotide 3'-phosphodiesterase 2 (CNP2). Immunoblot analysis indicated that both CNP1 and CNP2 isoforms are present in the CBL-PSD fraction, whereas there is little CNP2 in the forebrain (FB)-PSD fraction. Both isoforms in the CBL-PSD fraction were tyrosine-phosphorylated to a basal extent. They were efficiently dissociated from the complexes in the PSD fraction by salt, but not by non-ionic detergents such as n-octyl glucoside (OG) and Triton X-100. Immunocytochemistry of dissociated cerebellar cultures revealed patchy CNP staining in oligodendrocytes (OLs), Purkinje cells (PCs), and unidentified PSD95-positive cells, but no staining in granule cells (GCs). Our results indicate that both CNP1 and CNP2 are expressed in cerian populations of cerebellar cells in addition to OL, and that they are associated with complexes that are co-isolated with the PSD.
Assuntos
2',3'-Nucleotídeo Cíclico Fosfodiesterases/metabolismo , Cerebelo/citologia , Isoenzimas/metabolismo , Neurônios/metabolismo , Sinapses/metabolismo , Animais , Cerebelo/metabolismo , Detergentes , Camundongos , Neuroglia/citologia , Neuroglia/metabolismo , Neurônios/citologia , Peptídeos/metabolismo , Fosfotirosina/metabolismo , Ratos , Ratos Sprague-Dawley , Frações Subcelulares/química , Frações Subcelulares/metabolismoRESUMO
We investigated the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the expression of synaptic proteins in dissociated E18 rat cortical cells. TCDD (0-50 nM) was added to plating media, and cell viability and expression of synaptic proteins were assayed on 4 and 7 days in vitro (DIV), respectively. TCDD had no apparent effect on early neurite outgrowth 12 h after plating. However, on 4 DIV, cell viability was reduced significantly, and neurons often revealed vacuoles in 20 or 50 nM culture and had limited secondary or higher order dendritic processes in 20 or 50 nM culture. Immunoblot analyses of cell homogenates indicated upregulation of NMDA receptor subunits (NR1, NR2A, and NR2B), but downregulation of synaptic organizing proteins (PSD-95, densin-180, and septin6 homologue) and a synapse-enriched enzyme (alphaCaMKII). Changes in the expression of synaptic proteins may be a underlying mechanism for altered synaptic transmission and neuropathy by TCDD.
Assuntos
Córtex Cerebral/metabolismo , Poluentes Ambientais/farmacologia , Dibenzodioxinas Policloradas/farmacologia , Sinapses/metabolismo , Animais , Linhagem Celular , Poluentes Ambientais/toxicidade , Técnicas In Vitro , Dibenzodioxinas Policloradas/toxicidade , Ratos , Receptores de N-Metil-D-Aspartato/biossíntese , Receptores de N-Metil-D-Aspartato/genética , Sinapses/efeitos dos fármacosRESUMO
The postsynaptic density (PSD) is a proteinaceous cellular structure that is specialized for postsynaptic signal transduction. Here, we show that eukaryotic translation factor-1A (eEF1A; formerly known as eEF-1alpha) is associated with the excitatory PSD in rat forebrain. Immunoblot analysis showed that eEF1A in the PSD fraction is enriched over homogenate. Salt (1.0M NaCl), but not non-ionic detergents such as Triton X-100 (1.0%) and n-octyl glucoside (1.0%), could dissociate eEF1A from the PSD core. In cultured cortical neurons, eEF1A was colocalized with postsynaptic markers (PSD95 and SynGAPalpha), but not with a presynaptic marker (synaptophysin). These results indicate that eEF1A is present in the PSD of the excitatory synapses.
Assuntos
Córtex Cerebral/metabolismo , Fator 1 de Elongação de Peptídeos/metabolismo , Animais , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/ultraestrutura , Immunoblotting , Prosencéfalo/citologia , Prosencéfalo/metabolismo , Prosencéfalo/ultraestrutura , Ratos , Transdução de Sinais , Sinapses/metabolismoRESUMO
This study examined a 55 kDa protein in the rat cerebellar postsynaptic density (PSD) fraction. The amino acid sequence of an HPLC-purified peptide derived from tryptic digestion of the protein was contained in eukaryotic translation elongation factor-1A (eEF1A, formerly known as eEF-1alpha). Immunoblot analysis showed that eEF1A is enriched in the PSD fraction and is tightly associated with the PSD 'core'. The association of eEF1A with the PSD was further evidenced by colocalization of the protein with PSD95, a PSD marker, in dissociated cerebellar cultures and immunoelectron microscopy of the adult rat cerebellum. Combined, our results indicate that eEF1A is associated with the PSD.
Assuntos
Cerebelo/química , Fator 1 de Elongação de Peptídeos/análise , Sinapses/química , Animais , Contagem de Células/métodos , Cerebelo/ultraestrutura , Ratos , Sinapses/ultraestruturaRESUMO
Fuel ethanol production is far more costly to produce than fossil fuels. There are a number of approaches to cost-effective fuel ethanol production from biomass. We characterized stress response of thermotolerant Saccharomyces cerevisiae KNU5377 during glucose-based batch fermentation at high temperature (40°C). S. cerevisiae KNU5377 (KNU5377) transcription factors (Hsf1, Msn2/4, and Yap1), metabolic enzymes (hexokinase, glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, and alcohol dehydrogenase), antioxidant enzymes (thioredoxin 3, thioredoxin reductase, and porin), and molecular chaperones and its cofactors (Hsp104, Hsp82, Hsp60, Hsp42, Hsp30, Hsp26, Cpr1, Sti1, and Zpr1) are upregulated during fermentation, in comparison to S. cerevisiae S288C (S288C). Expression of glyceraldehyde-3-phosphate dehydrogenase increased significantly in KNU5377 cells. In addition, cellular hydroperoxide and protein oxidation, particularly lipid peroxidation of triosephosphate isomerase, was lower in KNU5377 than in S288C. Thus, KNU5377 activates various cell rescue proteins through transcription activators, improving tolerance and increasing alcohol yield by rapidly responding to fermentation stress through redox homeostasis and proteostasis.
Assuntos
Etanol/metabolismo , Fermentação , Resposta ao Choque Térmico , Saccharomyces cerevisiae/metabolismo , Adaptação Fisiológica , Biocombustíveis , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Viabilidade Microbiana , Oxirredução , Estresse Oxidativo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Regulação para CimaRESUMO
The molecular mechanisms involved in the ability of yeast cells to adapt and respond to oxidative stress are of great interest to the pharmaceutical, medical, food, and fermentation industries. In this study, we investigated the time-dependent, cellular redox homeostasis ability to adapt to menadione-induced oxidative stress, using biochemical and proteomic approaches in Saccharomyces cerevisiae KNU5377. Time-dependent cell viability was inversely proportional to endogenous amounts of ROS measured by a fluorescence assay with 2',7'-dichlorofluorescin diacetate (DCFHDA), and was hypersensitive when cells were exposed to the compound for 60 min. Morphological changes, protein oxidation and lipid peroxidation were also observed. To overcome the unfavorable conditions due to the presence of menadione, yeast cells activated a variety of cell rescue proteins including antioxidant enzymes, molecular chaperones, energy-generating metabolic enzymes, and antioxidant molecules such as trehalose. Thus, these results show that menadione causes ROS generation and high accumulation of cellular ROS levels, which affects cell viability and cell morphology and there is a correlation between resistance to menadione and the high induction of cell rescue proteins after cells enter into this physiological state, which provides a clue about the complex and dynamic stress response in yeast cells.
Assuntos
Oxidantes/toxicidade , Estresse Oxidativo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/fisiologia , Estresse Fisiológico , Vitamina K 3/toxicidade , Antioxidantes/metabolismo , Citosol/química , Peroxidação de Lipídeos , Viabilidade Microbiana/efeitos dos fármacos , Oxirredução , Espécies Reativas de Oxigênio/análise , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMO
Cyclophilins are conserved cis-trans peptidyl-prolyl isomerase that are implicated in protein folding and function as molecular chaperones. The accumulation of Cpr1 protein to menadione in Saccharomyces cerevisiae KNU5377Y suggests a possibility that this protein may participate in the mechanism of stress tolerance. Stress response of S. cerevisiae KNU5377Y cpr1Δ mutant strain was investigated in the presence of menadione (MD). The growth ability of the strain was confirmed in an oxidant-supplemented medium, and a relationship was established between diminishing levels of cell rescue enzymes and MD sensitivity. The results demonstrate the significant effect of CPR1 disruption in the cellular growth rate, cell viability and morphology, and redox state in the presence of MD and suggest the possible role of Cpr1p in acquiring sensitivity to MD and its physiological role in cellular stress tolerance. The in vivo importance of Cpr1p for antioxidant-mediated reactive oxygen species (ROS) neutralization and chaperone-mediated protein folding was confirmed by analyzing the expression changes of a variety of cell rescue proteins in a CPR1-disrupted strain. The cpr1Δ to the exogenous MD showed reduced expression level of antioxidant enzymes, molecular chaperones, and metabolic enzymes such as nicotinamide adenine dinucleotide phosphate (NADPH)- or adenosine triphosphate (ATP)-generating systems. More importantly, it was shown that cpr1Δ mutant caused imbalance in the cellular redox homeostasis and increased ROS levels in the cytosol as well as mitochondria and elevated iron concentrations. As a result of excess ROS production, the cpr1Δ mutant provoked an increase in oxidative damage and a reduction in antioxidant activity and free radical scavenger ability. However, there was no difference in the stress responses between the wild-type and the cpr1Δ mutant strains derived from S. cerevisiae BY4741 as a control strain under the same stress. Unlike BY4741, KNU5377Y Cpr1 protein was decarbonylated during MD stress. Decarbonylation of Cpr1 protein in KNU5377Y strain seems to be caused by a rapid and efficient gene expression program via stress response factors Hsf1, Yap1, and Msn2. Hence, the decarbonylated Cpr1 protein may be critical in cellular redox homeostasis and may be a potential chaperone to menadione.
Assuntos
Ciclofilina A/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Vitamina K 3/farmacologia , Antioxidantes/farmacologia , Ciclofilina A/fisiologia , Estresse Oxidativo , Dobramento de Proteína , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/fisiologia , Proteínas de Saccharomyces cerevisiae/fisiologia , Vitamina K 3/químicaRESUMO
OBJECTIVES: The cellular function of cyclophilin A (CypA) differs between organisms, even though CypA is conserved in both prokaryotes and eukaryotes. The purpose of this study was to elucidate the role of activated CypA isoform CPR1 in the antioxidative mechanisms of Saccharomyces cerevisiae under menadione (MD)-induced oxidative stress. METHODS: Four S. cerevisiae strains, KNU5377Y (kwt) and BY4741 (bwt), and their isogenic cpr1â¿ mutant strains (kc1 and bc1), were treated with MD, at a concentration ranging between 0.25 and 0.4 mM. Cpr1-mediated antioxidative effects were analyzed by measuring the levels of cellular glutathione (GSH) and ascorbate (AsA)-like molecules in yeast. RESULTS: GSH and AsA-like reductant molecule concentrations were more reduced in the presence of MD in the kc1 strain than in the kwt strain; whereas, there was no significant difference between the bwt and bc1 strains under the same conditions. In kc1 strain samples, we observed a reduction in the expression of proteins related both to GSH synthesis and the recycling system, and simultaneously, downregulation of GSH synthetase and GSH reductase activities were also evident. Oxidative stress in the kc1 strain was alleviated by the application of the GSH and AsA analog. CONCLUSION: These results indicate that activated Cpr1 modulates the response of antioxidant molecules involved in cellular redox homeostasis of KNU5377Y during oxidative stress induced by MD.
RESUMO
When proteins are damaged under stresses conditions, these proteins are either refolded or degraded by quality control system of molecular chaperones and protease. High-temperature requirement A (htrA) is of particular interest because it can perform the roles of both protease and a chaperone. HtrA plays an important role in maintaining the physiological homeostasis of bacteria against environmental stress such as elevated temperature, oxidative and osmotic stress. Inactivation of htrA genes can thus restrict the survival ability of bacteria. These observations suggested that htrA might be responsible for acid tolerance of Streptococcus mutans. In this study, we have generated an htrA mutant and an htrA-complemented strain of S. mutans K7 isolated from a Korean in order to investigate the role of htrA in growth under acidic conditions. In terms of growth under cidic conditions, the htrA mutant exhibited 20% to 23% lower growth than the control group. In addition, glucosyltransferase B and glucosyltransferase C expression levels significantly decreased. When the htrA expression level was restored by adding the htrA gene to the htrA mutant strain, the normal growth phenotype was restored under acid stress. Further, similar results were obtained for S. mutans UA159. Thus, htrA in S. mutans K7, as well as S. mutans UA159, can be concluded to play an important role during acid stress.
Assuntos
Proteínas de Bactérias/fisiologia , Chaperonas Moleculares/fisiologia , Peptídeo Hidrolases/fisiologia , Streptococcus mutans/genética , Proteínas de Bactérias/genética , Sequência de Bases , Criança , Sistemas Computacionais , Cárie Dentária/microbiologia , Farmacorresistência Bacteriana , Indução Enzimática , Regulação Bacteriana da Expressão Gênica , Glucosiltransferases/biossíntese , Glucosiltransferases/genética , Humanos , Concentração de Íons de Hidrogênio , Coreia (Geográfico) , Ácido Láctico/farmacologia , Chaperonas Moleculares/genética , Dados de Sequência Molecular , Peptídeo Hidrolases/genética , Dobramento de Proteína , Proteínas Recombinantes de Fusão/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/enzimologia , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus mutans/isolamento & purificaçãoRESUMO
Haplotypes and allele frequencies of 12 STR loci included in the PowerPlex Y system (DYS391, DYS389I, DYS439, DYS389II, DYS438, DYS437, DYS19, DYS392, DYS393, DYS390, and DYS385a/b) were obtained from a sample of 569 unrelated individuals living in the central region of Korea. A total of 473 haplotypes were observed in the 569 individuals studied, of which 426 (90.06%) were unique. The overall haplotype diversity for the 12 Y-STR loci was 0.9985, and the discrimination capacity was 0.8313. In DYS439, we found a new intermediate-sized allele that added an A at base 3 upstream from the repeat region's first GATA motif. The allele was named 11 (U3Ains) according to its sequence structure.