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Results for “proteome mapping”

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PubMed2003

Proteomic analysis of changes in the extracellular matrix of Arabidopsis cell suspension cultures induced by fungal elicitors.

A proteomic approach has been applied to investigate changes in the extracellular matrix of Arabidopsis thaliana cell suspension cultures following treatments with two fungal pathogen elicitors, chitosan and extracts of Fusarium moniliforme. The oxidative burst and induction of glutathione S-transferase were used as markers for induction of the pathogen defence response. Changes in the cell wall and culture filtrate proteome were profiled. Proteins whose abundance changed reproducibly were analysed via matrix assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry (MS). An increase in the level of two classical cell wall proteins (a putative endochitinase and a polygalacturonase inhibiting protein) and two novel proteins (a putative receptor-like protein kinase and a probable apospory-associated protein) were seen at 24 hours following elicitation. The level of an unknown protein and a hypothetical protein, which has some homology to serine carboxypeptidases, were decreased at 24 hours post-elicitation. In the culture filtrate extracts, we identified two pathogen elicitor responsive proteins, a xyloglucan endo-1,4-beta-D glucanases (XEG) and a peroxidase. Using a combination of two-dimensional polyacrylamide gel electrophoresis, immunoblotting with a phosphotyrosine-specific antibody, and MALDI-TOF MS we discovered that spots that represent putative lectin receptor-like kinase, a putative endochitinase and a XEG possess phosphorylated tyrosine residues. The identification of phosphorylated bona fide cell wall proteins and a putative extracellular receptor-like kinase with no transmembrane domain implicate the existence of an extracellular phosphorylation network which could be involved in intercellular communication.

Arabidopsis↗

PubMed2006

Proteomic characterization of the effects of clofibrate on protein expression in rat liver.

Clofibrate is a peroxisome proliferator known to induce liver tumours in rats. A proteomics study was conducted to provide new insights into the molecular mechanisms of clofibrate-induced non-genotoxic hepatocarcinogenesis. Rats were treated with 250 mg/kg day clofibrate orally and sacrificed after 7 days. Proteins extracted from the liver were analysed by 2-DE using DIGE technology. The protein identification performed by MS showed that clofibrate induced up-regulation of 77 proteins and down-regulation of 27 proteins. The highest expression ratios corresponded to proteins involved in a series of biochemical pathways such as lipid metabolism, fatty acid metabolism, amino acid metabolism, protein metabolism, citric acid cycle, xenobiotic detoxification and oxidative stress. Proteins implicated in cell proliferation and apoptosis, such as prohibitin, 10-formyl tetrahydrofolate dehydrogenase, senescence marker protein-30, pyridoxine 5'-phosphate oxidase and vimentin, were also identified as being regulated. These results provide leads for further investigations into the molecular mechanisms of liver tumours induced by clofibrate. In addition, MS results showed that a series of regulated proteins were detected as several spots corresponding to different pI and/or M(r). Differential effects on those variants could result from specific PTM and could be a specific molecular signature of the clofibrate-induced protein expression modulation in rat liver.

Amino Acid Sequence↗

PubMed2006

Proteomic identification of proteins associated with the osmoregulatory transcription factor TonEBP/OREBP: functional effects of Hsp90 and PARP-1.

Hypertonicity (e.g., high NaCl) activates the transcription factor tonicity-responsive enhancer/osmotic response element-binding protein (TonEBP/OREBP), increasing transcription of protective genes. In the present studies, by stably expressing amino acids 1-547 of TonEBP/OREBP in HEK 293 cells and immunoprecipitating it plus associated proteins from the nuclei of cells exposed to high NaCl, we identify 14 proteins that are physically associated with TonEBP/OREBP. The associated proteins fall into several classes: 1) DNA-dependent protein kinase, both its catalytic subunit and regulatory subunit, Ku86; 2) RNA helicases, namely RNA helicase A, nucleolar RNA helicase II/Gu, and DEAD-box RNA helicase p72; 3) small or heterogeneous nuclear ribonucleoproteins (snRNPs or hnRNPs), namely U5 snRNP-specific 116 kDa protein, U5 snRNP-specific 200 kDa protein, hnRNP U, hnRNP M, hnRNP K, and hnRNP F; 4) heat shock proteins, namely Hsp90beta and Hsc70; and 5) poly(ADP-ribose) polymerase-1 (PARP-1). We confirm identification of most of the proteins by Western analysis and also demonstrate by electrophoretic mobility-shift assay that they are present in the large complex that binds specifically along with TonEBP/OREBP to its cognate DNA element. In addition, we find that PARP-1 and Hsp90 modulate TonEBP/OREBP activity. PARP-1 expression reduces TonEBP/OREBP transcriptional activity and the activity of its transactivating domain. Hsp90 enhances those activities and sustains the increased abundance of TonEBP/OREBP protein in cells exposed to high NaCl.

Aldehyde Reductase↗

PubMed2006

Regression analysis for comparing protein samples with 16O/18O stable-isotope labeled mass spectrometry.

MOTIVATION: Using stable isotopes in global proteome scans, labeled molecules from one sample are pooled with unlabeled molecules from another sample and subsequently subjected to mass-spectral analysis. Stable-isotope methodologies make use of the fact that identical molecules of different stable-isotope compositions are differentiated in a mass spectrometer and are represented in a mass spectrum as distinct isotopic clusters with a known mass shift. We describe two multivariable linear regression models for (16)O/(18)O stable-isotope labeled data that jointly model pairs of resolved isotopic clusters from the same peptide and quantify the abundance present in each of the two biological samples while concurrently accounting for peptide-specific incorporation rates of the heavy isotope. The abundance measure for each peptide from the two biological samples is then used in down-stream statistical analyses, e.g. differential expression analysis. Because the multivariable regression models are able to correct for the abundance of the labeled peptide that appear as an unlabeled peptide due to the inability to exchange the natural C-terminal oxygen for the heavy isotope, they are particularly advantageous for a two-step digestion/labeling procedure. We discuss how estimates from the regression model are used to quantify the variability of the estimated abundance measures for the paired samples. Although discussed in the context of (16)O/(18)O stable-isotope labeled data, the multivariable regression models are generalizable to other stable-isotope labeled technologies.

Algorithms↗

PubMed2003

Greedily building protein networks with confidence.

MOTIVATION: With genome sequences complete for human and model organisms, it is essential to understand how individual genes and proteins are organized into biological networks. Much of the organization is revealed by proteomics experiments that now generate torrents of data. Extracting relevant complexes and pathways from high-throughput proteomics data sets has posed a challenge, however, and new methods to identify and extract networks are essential. We focus on the problem of building pathways starting from known proteins of interest. RESULTS: We have developed an efficient, greedy algorithm, SEEDY, that extracts biologically relevant biological networks from protein-protein interaction data, building out from selected seed proteins. The algorithm relies on our previous study establishing statistical confidence levels for interactions generated by two-hybrid screens and inferred from mass spectrometric identification of protein complexes. We demonstrate the ability to extract known yeast complexes from high-throughput protein interaction data with a tunable parameter that governs the trade-off between sensitivity and selectivity. DNA damage repair pathways are presented as a detailed example. We highlight the ability to join heterogeneous data sets, in this case protein-protein interactions and genetic interactions, and the appearance of cross-talk between pathways caused by re-use of shared components. SIGNIFICANCE AND COMPARISON: The significance of the SEEDY algorithm is that it is fast, running time O[(E + V) log V] for V proteins and E interactions, a single adjustable parameter controls the size of the pathways that are generated, and an associated P-value indicates the statistical confidence that the pathways are enriched for proteins with a coherent function. Previous approaches have focused on extracting sub-networks by identifying motifs enriched in known biological networks. SEEDY provides the complementary ability to perform a directed search based on proteins of interest. AVAILABILITY: SEEDY software (Perl source), data tables and confidence score models (R source) are freely available from the author.

Algorithms↗

PubMed2006

Epl1, the major secreted protein of Hypocrea atroviridis on glucose, is a member of a strongly conserved protein family comprising plant defense response elicitors.

We used a proteomic approach to identify constitutively formed extracellular proteins of Hypocrea atroviridis (Trichoderma atroviride), a known biocontrol agent. The fungus was cultivated on glucose and the secretome was examined by two-dimensional gel electrophoresis. The two predominant spots were identified by MALDI MS utilizing peptide mass fingerprints and amino acid sequence tags obtained by postsource decay and/or high-energy collision-induced dissociation (MS/MS) experiments, and turned out to be the same protein (12 629 Da as determined with MS, pI 5.5-5.7), probably representing the monomer and the dimer. The corresponding gene was subsequently cloned from H. atroviridis and named epl1 (eliciting plant response-like), because it encodes a protein that exhibits high similarity to the cerato-platanin family, which comprises proteins such as cerato-platanin from Ceratocystis fimbriata f. sp. platani and Snodprot1 of Phaeosphaeria nodorum, which have been reported to be involved in plant pathogenesis and elicitation of plant defense responses. Additionally, based on the similarity of the N-terminus to that of H. atroviridis Epl1, we conclude that a previously identified 18 kDa plant response elicitor isolated from T. virens is an ortholog of epl1. Our results showed that epl1 transcript was present under all growth conditions tested, which included the carbon sources glucose, glycerol, l-arabinose, d-xylose, colloidal chitin and cell walls of the plant pathogen Rhizoctonia solani, and also plate confrontation assays with R. solani. Epl1 transcript could even be detected under osmotic stress, and carbon and nitrogen starvation.

Amino Acid Sequence↗

PubMed2004

Proteomic characterization of the interstitial fluid perfusing the breast tumor microenvironment: a novel resource for biomarker and therapeutic target discovery.

Clinical cancer proteomics aims at the identification of markers for early detection and predictive purposes, as well as to provide novel targets for drug discovery and therapeutic intervention. Proteomics-based analysis of traditional sources of biomarkers, such as serum, plasma, or tissue lyzates, has resulted in a wealth of information and the finding of several potential tumor biomarkers. However, many of these markers have shown limited usefulness in a clinical setting, underscoring the need for new clinically relevant sources. Here we present a novel and highly promising source of biomarkers, the tumor interstitial fluid (TIF) that perfuses the breast tumor microenvironment. We collected TIFs from small pieces of freshly dissected invasive breast carcinomas and analyzed them by two-dimensional polyacrylamide gel electrophoresis in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Western immunoblotting, as well as by cytokine-specific antibody arrays. This approach provided for the first time a snapshot of the protein components of the TIF, which we show consists of more than one thousand proteins--either secreted, shed by membrane vesicles, or externalized due to cell death--produced by the complex network of cell types that make up the tumor microenvironment. So far, we have identified 267 primary translation products including, but not limited to, proteins involved in cell proliferation, invasion, angiogenesis, metastasis, inflammation, protein synthesis, energy metabolism, oxidative stress, the actin cytoskeleton assembly, protein folding, and transport. As expected, the TIF contained several classical serum proteins. Considering that the protein composition of the TIF reflects the physiological and pathological state of the tissue, it should provide a new and potentially rich resource for diagnostic biomarker discovery and for identifying more selective targets for therapeutic intervention.

Adult↗

PubMed2004

Depth of proteome issues: a yeast isotope-coded affinity tag reagent study.

As a test case for optimizing how to perform proteomics experiments, we chose a yeast model system in which the UPF1 gene, a protein involved in nonsense-mediated mRNA decay, was knocked out by homologous recombination. The results from five complete isotope-coded affinity tag (ICAT) experiments were combined, two using matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry (MS/MS) and three using electrospray MS/MS. We sought to assess the reproducibility of peptide identification and to develop an informatics structure that characterizes the identification process as well as possible, especially with regard to tenuous identifications. The cleavable form of the ICAT reagent system was used for quantification. Most proteins did not change significantly in expression as a consequence of the upf1 knockout. As expected, the Upf1 protein itself was down-regulated, and there were reproducible increases in expression of proteins involved in arginine biosynthesis. Initially, it seemed that about 10% of the proteins had changed in expression level, but after more thorough examination of the data it turned out that most of these apparent changes could be explained by artifacts of quantification caused by overlapping heavy/light pairs. About 700 proteins altogether were identified with high confidence and quantified. Many peptides with chemical modifications were identified, as well as peptides with noncanonical tryptic termini. Nearly all of these modified peptides corresponded to the most abundant yeast proteins, and some would otherwise have been attributed to "single hit" proteins at low confidence. To improve our confidence in the identifications, in MALDI experiments, the parent masses for the peptides were calibrated against nearby components. In addition, five novel parameters reflecting different aspects of identification were collected for each spectrum in addition to the Mascot score that was originally used. The interrelationship between these scoring parameters and confidence in protein identification is discussed.

Amino Acid Sequence↗

PubMed2005

Exploring the charge space of protein-protein association: a proteomic study.

The rate of association of a protein complex is a function of an intrinsic basal rate and of the magnitude of electrostatic steering. In the present study we analyze the contribution of electrostatics towards the association rate of proteins in a database of 68 transient hetero-protein-protein complexes. Our calculations are based on an upgraded version of the computer algorithm PARE, which was shown to successfully predict the impact of mutations on k(on) by calculating the difference in Columbic energy of interaction of a pair of proteins. HyPare (http://bip.weizmann.ac.il/HyPare), automatically calculates the impact of mutations on a per-residue basis for all residues of a protein-protein interaction, achieving a precision similar to that of PARE. Our calculations show that electrostatics play a marginal role (<10 fold) in determining the rate of association for about half of the complexes in the database. Strong electrostatic steering, which results in an increase of over 100-fold in k(on), was calculated for about 25% of the complexes. Applying HyPare to all 68 complexes in the database shows that a small number of residues are hotspots for association. About 40% of the hotspots are calculated to increase the rate of association upon mutation, and thus increase binding affinity. This is a much higher ratio than found for hotspots for dissociation, where the large majority cause weaker binding. About 40% of the hotspots are located outside the physical boundary of the binding site, making them ideal candidates for protein engineering. Our data shows that a majority of protein-protein complexes are not optimized for fast association. Hotspots are not evenly distributed between all types of amino acids. About 75% of all hotspots are of charged residues. This is understandable, as a charge-reverse mutant changes the total charge by 2. The small number of hydrophobic residues that are hotspots upon mutation probably relates to their location and surrounding. For 18 out of the 68 complexes in the database, experimental values of k(on) are available. For these, a basal rate of association was calculated to be in the range of 10(4)M(-1)s(-1) to 10(7)M(-1)s(-1). Some of these rates were verified independently from experimental mutant data. The basal rates were correlated with the size of the proteins and the shape of the interface.

Algorithms↗

PubMed2001

Differential protein expression in rat trigeminal ganglia during inflammation.

A proteomics approach was used to investigate global protein changes in rat sensory ganglia exposed to pro-inflammatory stimuli. Inflammation was provoked in vivo by injecting selected facial areas with Freunds Complete Adjuvant (FCA), or by stimulating freshly isolated trigeminal ganglia ex vivo with pro-inflammatory mediators (interleukin-1 beta, tumor necrosis factor-alpha, interferon-gamma). Following two-dimensional gel electrophoresis, silver staining and mass spectrometry, a protein reference map and database was generated for rat trigeminal ganglia, which to our knowledge is the first to be reported. Sixty-seven out of 85 selected protein spots were successfully identified using matrix-assisted laser desorption/ionization mass spectrometry. This reference map was used to monitor changes in the ganglia proteome induced during inflammation in vivo and ex vivo. In vivo we found that FCA treatment specifically induced differential protein expression of two unidentified protein spots and, to a lower extent, of beta-tubulin. Image analysis of ganglia treated ex vivo with the cocktail of cytokines indicated that some of the changes in the protein population were also observed in vivo after FCA treatment. If the cytokine stimulation was performed in the presence of acetaminophen (paracetamol), the drug seemed to reverse the effects of cytokine treatment for at least some protein spots, restoring the same protein pattern observed in control samples.

Animals↗

PubMed2002

Continuous sample deposition from reversed-phase liquid chromatography to tracks on a matrix-assisted laser desorption/ionization precoated target for the analysis of protein digests.

Peptide mass fingerprinting by matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS) is one of the standard high-throughput methods for protein identification today. Traditionally this method has been based on spotting peptide mixtures onto MALDI targets. While this method works well for more abundant proteins, low-abundance proteins mixed with high-abundance proteins tend to go undetected due to ion suppression effects, instrumental dynamic range limitations and chemical noise interference. We present an alternative approach where liquid chromatography (LC) effluent is continuously collected as linear tracks on a MALDI target. In this manner the chromatographic separation is spatially preserved on the target, which enables generation of off-line LC-MS and LC-MS/MS data by MALDI. LC-MALDI sample collection provides improved sensitivity and dynamic range, spatial resolution of peptides along the sample track, and permits peptide mass mapping of low-abundance proteins in mixtures containing high-abundance proteins. In this work, standard and ribosomal protein digests are resolved and captured using LC-MALDI sample collection and analyzed by MALDI-TOF-MS.

Amino Acid Sequence↗

PubMed2002

Mapping of phosphorylated proteins on two-dimensional polyacrylamide gels using protein phosphatase.

This study developed an enzymatic method for high-throughput mapping of phosphoproteins on two-dimensional (2-D) polyacrylamide gels. Proteins of cultured rat skin fibroblasts were divided into two aliquots, one of which was dephosphorylated using recombinant lambda protein phosphatase and the other was not treated with the enzyme. The two aliquots were then subjected to 2-D electrophoresis. Phosphoproteins could be mapped on the 2-D gel of the nontreated aliquot by comparing the gels of the two aliquots, because the phosphoproteins in the treated aliquot shifted to more basic positions on the gel. This technique revealed that approximately 5% of the detectable proteins were phosphorylated. Fourteen phosphoproteins were identified by mass spectrometry, including proteasome component C8 and small glutamine-rich tetratricopeptide repeat-containing protein. Furthermore, the extent of phosphorylation of two actin modulating proteins, destrin and cofilin, was found to be significantly reduced when the cells were chemically or enzymatically detached from the culture dishes. The method developed by this study can generally be applied to all biological materials and is useful for high-throughput mapping of phosphoproteins in proteome research.

Animals↗

PubMed2003

An optimized method for the isolation and identification of membrane proteins.

The purpose of this study was to develop a protocol suitable for membrane protein extraction from limited starting material and to identify appropriate conditions for two-dimensional (2-D) gel electrophoresis. We used A549 cells, a human alveolar type II cell line, and evaluated three protein extraction methods based on different separation principles, namely protein solubility, detergent-based and density-based organelle separation. Detergent-based extraction achieved the highest yield with 14.64% +/- 2.35 membrane proteins but sequential extraction with 7.35% +/- 0.78 yield and centrifugal extraction with 4.1% +/- 0.54 yield produced the purest fractionation of membrane proteins. Only the sequential and the detergent-based extraction proved suitable for small volumes of starting material. We identified annexin I + II, electron transfer flavoprotein beta-chain, H(+)-transporting ATP synthase, mitofilin and protein disulfide isomerase A3 as membrane and cytokeratin 8 + 18, actin and others as soluble proteins using matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis and started to map the A549 cell proteome. Our data suggest that membrane proteins can be extracted efficiently from small samples using a simple sequential protein extraction method. They can be separated and identified successfully using optimized conditions in 2-D gel electrophoresis. The presented methods will be useful for further investigations of membrane proteins of alveolar and bronchial carcinomas.

Cell Fractionation↗

PubMed2005

Peptide mass fingerprinting by matrix-assisted laser desorption ionization mass spectrometry of proteins detected by immunostaining on nitrocellulose.

We have developed an approach that allows peptide mass mapping by matrix-assisted laser desorption ionization-mass spectrometry of proteins visualized on a nitrocellulose membrane by immunochemical detection. Proteins are separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), electroblotted onto a nitrocellulose membrane and after blocking with a nonprotein-containing polymer such as polyvinylpyrrolidone 40 (PVP-40) or Tween 20, the proteins are stained with fount India ink. After incubation with primary and, if required, secondary peroxidase-coupled antibodies, immunochemically reactive proteins can be visualized using conventional enhanced chemiluminescence detection and assigned to the India ink-stained membrane by simple superposition. The proteins of interest are excised, submitted to "on-membrane" cleavage and the peptides are analyzed by mass spectrometry. Protein-based blocking reagents normally used in standard immunodetection protocols, such as skimmed milk, can be employed. We have obtained high-quality mass spectra of bovine serum albumin (BSA) detected on an immunoblot with an estimated amount of 100 fmol applied onto the gel, indicating the sensitivity of the present method. In addition, the approach is demonstrated with two other commercially available proteins, a serum protein, the successful identification of a tyrosine phosphorylated protein from total rat liver homogenate and serine phosphorylated proteins from an EcR 293 nuclear extract separated by two-dimensional (2-D) SDS-PAGE.

Animals↗

PubMed2004

Assessment of protein spot components applying correspondence analysis for peptide mass fingerprint data.

Proteins separated by two-dimensional gel electrophoresis (2-DE) may be distributed over several spots. Otherwise, one spot may contain more than one component. The same protein occurring in several spots supposedly represents differently modified protein species that might be of biological relevance. Identification of spots with peptide mass fingerprinting and database searching leads only to the detection of the major spot components. If a spot also contains additional minor protein components, quantitation of spots with protein staining techniques or antibody detection becomes misleading. In order to find spots containing minor components we applied correspondence analysis, a multivariate data exploration method, to peptide mass fingerprint data. Correspondence analysis using peak lists revealed groups of spots containing the same protein with their characteristic mass-to-charge ratio (m/z) values. In order to detect different protein spot components an interactive threshold setting and removal of m/z values with subsequent recalculation of the correspondence analysis using our software tool CorrAn are performed. The usefulness of this methodical approach was shown by a data set of peptide mass fingerprints of 284 spots of Helicobacter pylori 26695 separated by 2-DE.

Bacterial Proteins↗

PubMed2005

Proteome analysis of brown spider venom: identification of loxnecrogin isoforms in Loxosceles gaucho venom.

Brown spiders of the Loxosceles genus are distributed worldwide. In Brazil, eight species are found in Southern states, where the envenomation by Loxosceles venom (loxoscelism) is a health problem. The mechanism of the dermonecrotic action of Loxosceles venom is not totally understood. Two isoforms of dermonecrotic toxins (loxnecrogins) from L. gaucho venom have been previously purified, and showed sequence similarities to sphingomyelinase. Herein we employed a proteomic approach to obtain a global view of the venom proteome, with a particular interest in the loxnecrogin isoforms' pattern. Proteomic two-dimensional gel electrophoresis maps for L. gaucho, L. intermedia, and L. laeta venoms showed a major protein region (30-35 kDa, pI 3-10), where at least eight loxnecrogin isoforms could be separated and identified. Their characterization used a combined approach composed of Edman chemical sequencing, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and electrospray ionization-quadropole-time of flight tandem mass spectrometry leading to the identification of sphingomyelinases D. The venom was also pre-fractionated by gel filtration on a Superose 12 fast protein liqiud chromatography column, followed by capillary liquid chromatography-mass spectrometry. Eleven possible loxnecrogin isoforms around 30-32 kDa were detected. The identification of dermonecrotic toxin isoforms in L. gaucho venom is an important step towards understanding the physiopathology of the envenomation, leading to improvements in the immunotherapy of loxoscelism.

Amino Acid Sequence↗

PubMed2006

Functional and phenotypic relevance of differentially expressed proteins in calcineurin mutants of Caenorhabditis elegans.

Calcineurin is a heterodimeric serine/threonine protein phosphatase, important for many cellular processes such as T-cell regulation, cardiac hypertrophy and kidney development. We previously reported the characterization of Caenorhabditis elegans calcineurin mutants as providing a simple but excellent genetic model system for studying in vivo functions of calcineurin. Calcineurin loss-of-function mutants, cnb-1(lf), and gain-of-function mutants, tax-6(gf), show certain opposite phenotypes as well as some similar phenotypes. In order to explain the phenotypic similarity observed in both loss-of-function and gain-of-function mutants, we examined the proteins that followed similar trends in both mutants relative to wild-type worms by using 2-DE. Interestingly, VHA-13, HSP-6 and phosphoenolpyruvate carboxykinase are down-regulated in both mutants. A total of 96 differentially regulated proteins were identified by MALDI-TOF/MS. Among these, 42 proteins are up-regulated and 54 proteins are down-regulated in calcineurin mutants. Furthermore, knock-down of about 30% of the genes, which are down-regulated in calcineurin mutants, showed some of the phenotypes of calcineurin-null mutants. This analysis suggests the functional relevance of these proteins to calcineurin activity in C. elegans.

Animals↗

PubMed2006

Differential protein expression in hypertrophic heart with and without hypertension in spontaneously hypertensive rats.

Although cardiac hypertrophy in hypertension has been well recognized, the molecular mechanisms for the development of hypertrophy are still largely unknown. In this study, the protein expression profiles of left ventricular myocardia in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at different ages were analyzed using 2-DE in combination with MALDI-TOF/TOF MS/MS. The results showed that 20 proteins were modulated in the hypertrophic myocardium. Out of these modulated proteins, 13 proteins presented significant changes in SHR at an early stage prior to the development of sustained hypertension, while the changes of the other 7 protein expressions occurred only at a late stage in SHR when the blood pressure was significantly elevated, and were largely reversible by treatment with rennin-angiotensin-aldosterone system inhibitors losartan or enalapril. These data demonstrate that the changes in energy metabolism in the hypertrophied heart favor an increase in glycolysis and a decrease in oxidation of fatty acid and glucose, which occur at an early stage in SHR without hypertension. Our results also provide evidence to support the hypothesis that oxidative stress plays an important role in the development of hypertensive cardiac hypertrophy.

Age Factors↗