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1.
Ann Glob Health ; 87(1): 108, 2021.
Article in English | MEDLINE | ID: mdl-34824989

ABSTRACT

Background: Migration is at an all-time high worldwide, and despite increased focus on international migrants, there is little evidence about internal migrants' exposures to socioeconomic, occupational, and environmental risk factors in low-and middle-income countries. Objective: The aim of this study was to examine differences in occupational health and access to water, sanitation, and hygiene (WASH) between internal migrants and non-migrants. Methods: A face-to-face survey (n = 937) was conducted in Mandalay, Myanmar. Bivariate and multivariate analysis included traditional social determinants such as education, income, occupation, gender, age, and location in addition to internal migration status. Findings: The majority of internal migrants (23% of the total sample) were labor migrants (67.3%), and while common social determinants (e.g., household income, education, and gender) were not statistically different between migrants and non-migrants, these groups reported different occupational profiles (p < 0.001). Migrants had higher odds of being street vendors (AOR = 2.26; 95% CI 1.33-3.85; p = 0.003) and were less likely to work labor jobs such as in factories or construction (AOR = 0.44; 95% CI 0.19-1.00; p = 0.051) when controlling for age, gender, education, and location. Internal migrants had significantly greater probabilities of experiencing some injuries and illness symptoms, such as cuts, vomiting, coughing, heatstroke, and diarrhea at work (p < 0.001). Compared to non-migrants, migrants' households were approximately three times more likely (AOR = 3.45; 95% CI 2.17-5.62; p < 0.001) to have an unimproved source of drinking water and twice as likely (AOR = 1.98; 95% CI 1.10-3.58; p < 0.05) to have unimproved sanitation facilities in their homes. Conclusions: The results underscore the importance of considering internal migration as an aspect of social determinants analyses, and the need for targeting appropriate WASH interventions to address inequities.


Subject(s)
Occupational Health , Sanitation , Humans , Hygiene , Myanmar/epidemiology , Social Determinants of Health , Socioeconomic Factors , Water
2.
Sci Rep ; 11(1): 10203, 2021 05 13.
Article in English | MEDLINE | ID: mdl-33986354

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a major health concern globally. Genomic epidemiology is an important tool to assess the pandemic of coronavirus disease 2019 (COVID-19). Several mutations have been reported by genome analysis of the SARS-CoV-2. In the present study, we investigated the mutational and phylogenetic analysis of 30 whole-genome sequences for the virus's genomic characteristics in the specimens collected in the early phase of the pandemic (March-June, 2020) and the sudden surge of local transmission (August-September, 2020). The four samples in the early phase of infection were B.6 lineage and located within a clade of the samples collected at the same time in Singapore and Malaysia, while five returnees by rescue flights showed the lineage B. 1.36.1 (three from India), B.1.1 (one from India) and B.1.80 (one from China). However, there was no evidence of local spread from these returnees. Further, all 19 whole-genome sequences collected in the sudden surge of local transmission showed lineage B.1.36. The surge of the second wave on SARS-CoV-2 infection was linked to the single-introduction of a variant (B.1.36) that may result from the strict restriction of international travel and containment efforts. These genomic data provides the useful information to disease control and prevention strategy.


Subject(s)
COVID-19/epidemiology , COVID-19/virology , SARS-CoV-2/genetics , COVID-19/diagnosis , Genome, Viral , Humans , Mutation , Myanmar/epidemiology , SARS-CoV-2/isolation & purification , Whole Genome Sequencing
3.
Article in English | MEDLINE | ID: mdl-32106467

ABSTRACT

The study objective was to examine barriers and facilitators of maternal health services utilization in Myanmar with the highest maternal mortality ratio in Southeast Asia. Data for 258 mothers with children under five were extracted from a community health survey administered between 2016 and 2017 in Mandalay, the largest city in central Myanmar, and analyzed for associations between determinants of maternal health care choices and related outcomes. The study showed that late antenatal care was underutilized (41.7%), and antenatal care attendance was significantly associated with geographical setting, household income, education, and access to transportation (p ≤ 0.05). Less than one-third of women gave birth at home and 18.5% of them did so without the assistance of traditional birth attendants. Household education level was a significant predictor for home delivery (p < 0.01). Utilization of postnatal care services was irregular (47.9%-70.9%) and strongly associated with women's places of delivery (p < 0.01). Efforts geared towards improving maternal health outcomes should focus on supporting traditional birth attendants in their role of facilitating high-quality care and helping women reach traditional health facilities, as well as on maternal health literacy based on culturally appropriate communication.


Subject(s)
Maternal Health Services , Maternal Health , Patient Acceptance of Health Care , Adult , Child , Communication , Cultural Competency , Delivery, Obstetric , Female , Health Literacy , Humans , Myanmar , Pregnancy , Prenatal Care
4.
Cell Rep ; 26(11): 3100-3115.e7, 2019 03 12.
Article in English | MEDLINE | ID: mdl-30865897

ABSTRACT

Modern omics technologies allow us to obtain global information on different types of biological networks. However, integrating these different types of analyses into a coherent framework for a comprehensive biological interpretation remains challenging. Here, we present a conceptual framework that integrates protein interaction, phosphoproteomics, and transcriptomics data. Applying this method to analyze HRAS signaling from different subcellular compartments shows that spatially defined networks contribute specific functions to HRAS signaling. Changes in HRAS protein interactions at different sites lead to different kinase activation patterns that differentially regulate gene transcription. HRAS-mediated signaling is the strongest from the cell membrane, but it regulates the largest number of genes from the endoplasmic reticulum. The integrated networks provide a topologically and functionally resolved view of HRAS signaling. They reveal distinct HRAS functions including the control of cell migration from the endoplasmic reticulum and TP53-dependent cell survival when signaling from the Golgi apparatus.


Subject(s)
Cell Compartmentation , Proto-Oncogene Proteins p21(ras)/metabolism , Signal Transduction , Apoptosis , Cell Membrane/metabolism , Endoplasmic Reticulum/metabolism , HeLa Cells , Humans , Protein Interaction Maps , Protein Processing, Post-Translational , Proto-Oncogene Proteins p21(ras)/genetics , Transcriptome , Tumor Suppressor Protein p53
5.
Malar J ; 16(1): 333, 2017 08 14.
Article in English | MEDLINE | ID: mdl-28806957

ABSTRACT

BACKGROUND: Emergence of artemisinin-resistant malaria in Southeast Asian countries threatens the global control of malaria. Although K13 kelch propeller has been assessed for artemisinin resistance molecular marker, most of the mutations need to be validated. In this study, artemisinin resistance was assessed by clinical and molecular analysis, including k13 and recently reported markers, pfarps10, pffd and pfmdr2. METHODS: A prospective cohort study in 1160 uncomplicated falciparum patients was conducted after treatment with artemisinin-based combination therapy (ACT), in 6 sentinel sites in Myanmar from 2009 to 2013. Therapeutic efficacy of ACT was assessed by longitudinal follow ups. Molecular markers analysis was done on all available day 0 samples. RESULTS: True recrudescence treatment failures cases and day 3 parasite positivity were detected at only the southern Myanmar sites. Day 3 positive and k13 mutants with higher prevalence of underlying genetic foci predisposing to become k13 mutant were detected only in southern Myanmar since 2009 and comparatively fewer mutations of pfarps10, pffd, and pfmdr2 were observed in western Myanmar. K13 mutations, V127M of pfarps10, D193Y of pffd, and T448I of pfmdr2 were significantly associated with day 3 positivity (OR: 6.48, 3.88, 2.88, and 2.52, respectively). CONCLUSIONS: Apart from k13, pfarps10, pffd and pfmdr2 are also useful for molecular surveillance of artemisinin resistance especially where k13 mutation has not been reported. Appropriate action to eliminate the resistant parasites and surveillance on artemisinin resistance should be strengthened in Myanmar. Trial registration This study was registered with ClinicalTrials.gov, identifier NCT02792816.


Subject(s)
Antimalarials/pharmacology , Artemisinins/pharmacology , Drug Resistance , Malaria, Falciparum/drug therapy , Plasmodium falciparum/drug effects , Protozoan Proteins/genetics , Biomarkers , Myanmar , Plasmodium falciparum/genetics , Protozoan Proteins/metabolism
6.
Malar J ; 15: 308, 2016 06 06.
Article in English | MEDLINE | ID: mdl-27267877

ABSTRACT

BACKGROUND: After artemisinin resistance was reported, the Myanmar artemisinin resistance containment (MARC) project was initiated in 2011. One of the activities of MARC is to train volunteers for early diagnosis and prompt treatment by providing rapid diagnostic tests (RDT) and artemisinin combination therapy. This study aimed to fulfil the gap of information on the challenges faced by malaria volunteers in artemisinin-containment areas. METHODS: A cross-sectional, descriptive study was conducted in 11 townships in MARC areas to assess the challenges in early diagnosis of malaria and treatment by malaria volunteers using qualitative and quantitative approaches. RESULTS: Altogether 405 volunteers participated in the study. Although 97.5 % of volunteers can interpret a positive result for malaria, only 41.2 % correctly stated the persistence of a positive result in recently infected cases. Over 80 % knew the effects of temperature and humidity on performance of the malaria RDT. Unexpectedly, 15.1 % perceived that expired RDTs can still be useful for diagnosis although 98.3 % of respondents cited that the overall results of RDTs were reliable. Although most of them knew the treatment for malaria based on RDT results, some could not give the correct answer, while a few (2 %) mentioned artesunate monotherapy for RDT-negative cases. Training received by volunteers was also varied in study sites and 92.1 % believed that it was not sufficient. A certain portion of them faced the problem of regular supply of RDTs (9.9 %) and drugs (47.5 %), interpretation of result of RDTs (30 %), and performing blood test (20 %). The median RDT tested per month (25th, 75th percentile) was 6.0 (2.0, 15.0) indicating the need for prioritization based on endemicity. Regular reporting, supervision, monitoring system, and proper refresher training using uniform content of guideline to correct misconception of the volunteers, were needed to be strengthened. Moreover, the reliable and regular supply of materials and exchange system for expired RDTs and anti-malarials was important in the effectiveness of volunteers in MARC zones. CONCLUSIONS: Adequate refresher training, monitoring, supervision, and regular reliable supply of RDTs and anti-malarials were needed for capacity strengthening of volunteers in MARC zones.


Subject(s)
Antimalarials/administration & dosage , Antimalarials/pharmacology , Artemisinins/administration & dosage , Artemisinins/pharmacology , Drug Resistance , Malaria/diagnosis , Malaria/drug therapy , Attitude of Health Personnel , Community Health Workers , Cross-Sectional Studies , Drug Therapy, Combination/methods , Early Diagnosis , Education, Medical , Health Knowledge, Attitudes, Practice , Healthy Volunteers , Humans , Myanmar , Secondary Prevention
7.
Cell Rep ; 11(11): 1834-43, 2015 Jun 23.
Article in English | MEDLINE | ID: mdl-26074081

ABSTRACT

Although mass-spectrometry-based screens enable thousands of protein phosphorylation sites to be monitored simultaneously, they often do not cover important regulatory sites. Here, we hypothesized that this is due to the fact that nearly all large-scale phosphoproteome studies are initiated by trypsin digestion. We tested this hypothesis using multiple proteases for protein digestion prior to Ti(4+)-IMAC-based enrichment. This approach increases the size of the detectable phosphoproteome substantially and confirms the considerable tryptic bias in public repositories. We define and make available a less biased human phosphopeptide atlas of 37,771 unique phosphopeptides, correlating to 18,430 unique phosphosites, of which fewer than 1/3 were identified in more than one protease data set. We demonstrate that each protein phosphorylation site can be linked to a preferred protease, enhancing its detection by mass spectrometry (MS). For specific sites, this approach increases their detectability by more than 1,000-fold.


Subject(s)
Databases, Protein , Phosphopeptides/analysis , Protein Processing, Post-Translational , Proteolysis , Proteome/metabolism , Humans , Jurkat Cells , Phosphorylation , Proteome/chemistry , Trypsin/chemistry
8.
J Proteome Res ; 14(7): 2976-87, 2015 Jul 02.
Article in English | MEDLINE | ID: mdl-26066639

ABSTRACT

In phosphorylation-directed signaling, spatial and temporal control is organized by complex interaction networks that diligently direct kinases toward distinct substrates to fine-tune specificity. How these protein networks originate and evolve into complex regulatory machineries are among the most fascinating research questions in biology. Here, spatiotemporal signaling is investigated by tracing the evolutionary dynamics of each functional domain of cAMP-dependent protein kinase (PKA) and its diverse set of A-kinase anchoring proteins (AKAPs). Homologues of the catalytic (PKA-C) and regulatory (PKA-R) domains of the (PKA-R)2-(PKA-C)2 holoenzyme were found throughout evolution. Most variation was observed in the RIIa of PKA-R, crucial for dimerization and docking to AKAPs. The RIIa domain was not observed in all PKA-R homologues. In the fungi and distinct protist lineages, the RIIa domain emerges within PKA-R, but it displays large sequence variation. These organisms do not harbor homologues of AKAPs, suggesting that efficient docking to direct spatiotemporal PKA activity evolved in multicellular eukaryotes. To test this in silico hypothesis, we experimentally screened organisms with increasing complexity by cAMP-based chemical proteomics to reveal that the occurrence of PKA-AKAP interactions indeed coincided and expanded within vertebrates, suggesting a crucial role for AKAPs in the advent of metazoan multicellularity.


Subject(s)
Biological Evolution , Cyclic AMP-Dependent Protein Kinases/metabolism , Signal Transduction , Amino Acid Sequence , Animals , Catalytic Domain , Conserved Sequence , Molecular Sequence Data , Phylogeny , Proteomics , Sequence Homology, Amino Acid , Subcellular Fractions/enzymology
9.
Anal Chem ; 84(11): 4999-5006, 2012 Jun 05.
Article in English | MEDLINE | ID: mdl-22548487

ABSTRACT

In this manuscript, we present a proof-of-concept study for targeted relative protein quantitation workflow using chemical labeling in the form of dimethylation, coupled with selected reaction monitoring (dimethyl-SRM). We first demonstrate close to complete isotope incorporation for all peptides tested. The accuracy, reproducibility, and linear dynamic range of quantitation are further assessed based on known ratios of nonhuman standard proteins spiked into human cerebrospinal fluid (CSF) as a model complex matrix. Quantitation reproducibility below 20% (CV < 20%) was obtained for analyte concentrations present at a dynamic range of 4 orders of magnitude lower than that of the background proteins. An error of less than 15% was observed when measuring the abundance of 44 out of 45 major human plasma proteins. Dimethyl-SRM was further examined by comparing the relative quantitation of eight proteins in human CSF with the relative quantitation obtained using synthetic heavy peptides coupled to stable isotope dilution-SRM (SID-SRM). Comparison between the two methods reveals that the correlation between dimethyl-SRM and SID-SRM is within 0.3-33% variation, demonstrating the accuracy of relative quantitation using dimethyl-SRM. Dimethyl labeling coupled with SRM provides a fast, convenient, and cost-effective alternative for relative quantitation of a large number of candidate proteins/peptides.


Subject(s)
Blood Proteins/analysis , Isotope Labeling/methods , Peptides/cerebrospinal fluid , Proteomics/methods , Amino Acid Sequence , Humans , Indicator Dilution Techniques , Molecular Sequence Data , Reference Standards , Reproducibility of Results
10.
J Mol Cell Cardiol ; 52(2): 511-8, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21712045

ABSTRACT

Here we reveal that the characterization of large-scale re-arrangements of signaling scaffolds induced by heart failure can serve as a novel concept to identify more specific therapeutic targets. In the mammalian heart, the cAMP pathway, with the cAMP-dependent protein kinase (PKA) in a central role, acts directly downstream of adrenergic receptors to mediate cardiac contractility and rhythm. Heart failure, characterized by severe alterations in adrenergic stimulation is, amongst other interventions, often treated with ß-blockers. Contrasting results, however, have shown both beneficial and detrimental effects of decreased cAMP levels in failing hearts. We hypothesize that the origin of this behavior lies in the complex spatiotemporal organization of the regulatory subunit of PKA (PKA-R), which associates tightly with various A-kinase anchoring proteins (AKAPs) to specifically localize PKA's activity. Using chemical proteomics directly applied to human patient and control heart tissue we demonstrate that the association profile of PKA-R with several AKAPs is severely altered in the failing heart, for instance effecting the interaction between PKA and the novel AKAP SPHKAP was 6-fold upregulated upon failing heart conditions. Also a significant increase in captured cGMP-dependent protein kinase (PKG) and phosphodiesterase 2 (PDE2) was observed. The observed altered profiles can already explain many aspects of the aberrant cAMP-response in the failing human heart, validating that this dataset may provide a resource for several novel, more specific, treatment options. This article is part of a Special Issue entitled "Local Signaling in Myocytes".


Subject(s)
A Kinase Anchor Proteins/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Heart Failure/metabolism , Adult , Aged , Female , Humans , Male , Middle Aged , Myocardium/metabolism , Myofibrils/metabolism , Protein Binding , Protein Interaction Mapping , Proteome/metabolism , Signal Transduction , Young Adult
11.
Methods Mol Biol ; 803: 167-81, 2012.
Article in English | MEDLINE | ID: mdl-22065225

ABSTRACT

Chemical proteomics is a versatile tool to investigate protein-small molecule interactions, but can be extended to probe also secondary binding investigating small molecule-protein 1-protein 2 interactions, providing insight into protein scaffolds. This application of chemical proteomics has in particular been applied extensively to cyclic nucleotide (cAMP, cGMP) signaling. cAMP regulates cellular functions primarily by activating cAMP-dependent protein kinase (PKA). Compartmentalization of PKA plays an important role in the specificity of cAMP signaling events and is mediated by interaction of the regulatory subunit (PKA-R) with A-kinase anchoring proteins (AKAPs), which often form the core of even larger protein machineries. The selective binding of AKAPs to one of the major isoforms PKA-R type I (PKA-RI) and PKA-R type II (PKA-RII) is an important feature of cAMP/PKA signaling. However, this specificity is not well established for most AKAPs. Here, we describe a chemical proteomics approach that combines cAMP-based affinity chromatography with quantitative mass spectrometry to investigate PKA-R isoform/AKAP specificity directly in lysates of cells and tissues of any origin. With this tool, several novel PKA-R/AKAP specificities can be easily resolved.


Subject(s)
Protein Interaction Maps , Proteomics/methods , Amino Acid Sequence , Cell Extracts , Chemical Fractionation , Chromatography, Liquid , Cyclic AMP/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , HEK293 Cells , Humans , Ion Exchange , Isoenzymes/metabolism , Isotope Labeling , Mass Spectrometry , Molecular Sequence Data , Peptide Hydrolases/metabolism , Protein Binding , Software , Statistics as Topic
12.
Mol Biosyst ; 6(10): 1917-27, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20596566

ABSTRACT

The largest component of the human heart, the left ventricle (LV), plays a major role in delivering blood throughout the body. Therefore, an in-depth detailed quantitative proteome analysis of the human LV is a valuable resource. For this purpose, a multifaceted proteomics approach combining differential sample fractionations (gel, strong cation exchange (SCX)), enzymatic digestions (trypsin, chymotrypsin, LysN), and peptide fragmentation techniques (CID and ETcaD) was used to enhance protein sequence coverage, identification confidence and quantitative abundance determination. Using stringent criteria, 3584 distinct proteins could be identified from the latest well-annotated Swissprot database (23,000 entries). Commutatively, the over 130,000 identified MS/MS spectra were used to assess concentrations of each identified LV protein through a combination of spectral counting methods. Among the most concentrated proteins, many currently used biomarkers for detection of myocardial infarction reside. These cardiac leakage markers have a good diagnostic power, but their prognostic potential seems limited. Discovery of markers that represent etiological determinants of cardiac disease require a shift of focus towards the signaling proteome. Therefore, a protein-class centered quantitative analysis of kinases, phosphatases and GTPases was adopted. These comparative analyses revealed many cardiac involved kinases (PKA, CaMKII, ERK) to reside among the most abundant signaling proteins, and also to mediate many observed in vivo phosphorylation sites. The abundance chart of signaling proteins may assist in identifying novel functional pathways, for instance through the abundant, but relatively little known, kinases STK38L and OXSR1. The obtained quantitative protein library of the human left ventricle is a valuable resource to isolate signaling based, putative biomarkers with concentrations likely to be detectable in plasma.


Subject(s)
Heart Ventricles/metabolism , Muscle Proteins/metabolism , Proteome , Chromatography, Liquid , Databases, Protein , Heart Ventricles/enzymology , Humans , Phosphoprotein Phosphatases/metabolism , Phosphorylation , Protein Kinases/metabolism , Signal Transduction , Tandem Mass Spectrometry
13.
Chembiochem ; 11(7): 963-71, 2010 May 03.
Article in English | MEDLINE | ID: mdl-20394097

ABSTRACT

The compartmentalization of kinases and phosphatases plays an important role in the specificity of second-messenger-mediated signaling events. Localization of the cAMP-dependent protein kinase is mediated by interaction of its regulatory subunit (PKA-R) with the versatile family of A-kinase-anchoring proteins (AKAPs). Most AKAPs bind avidly to PKA-RII, while some have dual specificity for both PKA-RI and PKA-RII; however, no mammalian PKA-RI-specific AKAPs have thus far been assigned. This has mainly been attributed to the observation that PKA-RI is more cytosolic than the more heavily compartmentalized PKA-RII. Chemical proteomics screens of the cAMP interactome in mammalian heart tissue recently identified sphingosine kinase type 1-interacting protein (SKIP, SPHKAP) as a putative novel AKAP. Biochemical characterization now shows that SPHKAP can be considered as the first mammalian AKAP that preferentially binds to PKA-RIalpha. Recombinant human SPHKAP functions as an RI-specific AKAP that utilizes the characteristic AKAP amphipathic helix for interaction. Further chemical proteomic screening utilizing differential binding characteristics of specific cAMP resins confirms SPHKAPs endogenous specificity for PKA-RI directly in mammalian heart and spleen tissue. Immunolocalization studies revealed that recombinant SPHKAP is expressed in the cytoplasm, where PKA-RIalpha also mainly resides. Alignment of SPHKAPs' amphipathic helix with peptide models of PKA-RI- or PKA-RII-specific anchoring domains shows that it has largely only PKA-RIalpha characteristics. Being the first mammalian PKA-RI-specific AKAP with cytosolic localization, SPHKAP is a very promising model for studying the function of the less explored cytosolic PKA-RI signaling nodes.


Subject(s)
A Kinase Anchor Proteins/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Cyclic AMP-Dependent Protein Kinase Type I/metabolism , Cyclic AMP/chemistry , A Kinase Anchor Proteins/genetics , Adaptor Proteins, Signal Transducing/genetics , Amino Acid Sequence , Cell Line , Cyclic AMP-Dependent Protein Kinase Type I/analysis , Heart Ventricles/enzymology , Humans , Molecular Sequence Data , Protein Structure, Tertiary , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Alignment
14.
Mol Cell Proteomics ; 8(5): 1016-28, 2009 May.
Article in English | MEDLINE | ID: mdl-19119138

ABSTRACT

cAMP regulates cellular functions primarily by activating PKA. The involvement of PKAs in various signaling pathways occurring simultaneously in different cellular compartments necessitates stringent spatial and temporal regulation. This specificity is largely achieved by binding of PKA to protein scaffolds, whereby a distinct group of proteins called A kinase anchoring proteins (AKAPs) play a dominant role. AKAPs are a diverse family of proteins that all bind via a small PKA binding domain to the regulatory subunits of PKA. The binding affinities between PKA and several AKAPs can be different for different isoforms of the regulatory subunits of PKA. Here we employ a combination of affinity chromatography and mass spectrometry-based quantitative proteomics to investigate specificity in PKA-AKAP interactions. Three different immobilized cAMP analogs were used to enrich for PKA and its interacting proteins from several systems; HEK293 and RCC10 cells and rat lung and testis tissues. Stable isotope labeling was used to confidently identify and differentially quantify target proteins and their preferential binding affinity for the three different cAMP analogs. We were able to enrich all four isoforms of the regulatory subunits of PKA and concomitantly identify more than 10 AKAPs. A selective enrichment of the PKA RI isoforms could be achieved; which allowed us to unravel which AKAPs bind preferentially to the RI or RII regulatory domains of PKA. Of the twelve AKAPs detected, seven preferentially bound to RII, whereas the remaining five displayed at least dual specificity with a potential preference for RI. For some of these AKAPs our data provide the first insights into their specificity.


Subject(s)
Cyclic AMP-Dependent Protein Kinases/analysis , Cyclic AMP/chemistry , Protein Subunits/analysis , Resins, Synthetic/chemistry , A Kinase Anchor Proteins/metabolism , Animals , Chromatography, Affinity , Cyclic AMP/analogs & derivatives , Cyclic GMP-Dependent Protein Kinases/metabolism , Humans , Isoenzymes/analysis , Isotope Labeling , Lung/enzymology , Methylation , Microspheres , Protein Binding , Proteomics , Rats , Reproducibility of Results
15.
Proteomics ; 8(22): 4624-32, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18850632

ABSTRACT

Stable isotope labeling is at present one of the most powerful methods in quantitative proteomics. Stable isotope labeling has been performed at both the protein as well as the peptide level using either metabolic or chemical labeling. Here, we present a straightforward and cost-effective triplex quantification method that is based on stable isotope dimethyl labeling at the peptide level. Herein, all proteolytic peptides are chemically labeled at their alpha- and epsilon-amino groups. We use three different isotopomers of formaldehyde to enable the parallel analysis of three different samples. These labels provide a minimum of 4 Da mass difference between peaks in the generated peptide triplets. The method was evaluated based on the quantitative analysis of a cell lysate, using a typical "shotgun" proteomics experiment. While peptide complexity was increased by introducing three labels, still more than 1300 proteins could be identified using 60 microg of starting material, whereby more than 600 proteins could be quantified using at least four peptides per protein. The triplex labeling was further utilized to distinguish specific from aspecific cAMP binding proteins in a chemical proteomics experiment using immobilized cAMP. Thereby, differences in abundance ratio of more than two orders of magnitude could be quantified.


Subject(s)
Isotope Labeling/methods , Peptides/chemistry , Proteins/analysis , Proteomics/methods , Animals , Borohydrides/chemistry , Chromatography, Ion Exchange , Chromatography, Liquid , Cyclic AMP/analogs & derivatives , Cyclic AMP/chemistry , Cyclic AMP/metabolism , Formaldehyde/analogs & derivatives , Isomerism , Isotope Labeling/economics , Leukemia, Erythroblastic, Acute , Mass Spectrometry , Methylation , Protein Binding , Proteins/chemistry , Proteins/metabolism , Rats , Rats, Wistar , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry , Tumor Cells, Cultured
16.
Mass Spectrom Rev ; 27(4): 331-53, 2008.
Article in English | MEDLINE | ID: mdl-18381623

ABSTRACT

Mass spectrometry has evolved in recent years to a well-accepted and increasingly important complementary technique in molecular and structural biology. Here we review the many contributions mass spectrometry based studies have made in recent years in our understanding of the important cyclic nucleotide activated protein kinase A (PKA) and protein kinase G (PKG). We both describe the characterization of kinase isozymes, substrate phosphorylation, binding partners and post-translational modifications by proteomics based methodologies as well as their structural and functional properties as revealed by native mass spectrometry, H/D exchange MS and ion mobility. Combining all these mass spectrometry based data with other biophysical and biochemical data has been of great help to unravel the intricate regulation of kinase function in the cell in all its magnificent complexity.


Subject(s)
Cyclic AMP-Dependent Protein Kinases/chemistry , Mass Spectrometry/methods , Protein Kinase C/chemistry , Proteomics , Amino Acid Sequence , Animals , Humans , Isoenzymes/chemistry , Molecular Sequence Data , Structure-Activity Relationship
17.
Anal Chem ; 77(18): 5814-22, 2005 Sep 15.
Article in English | MEDLINE | ID: mdl-16159110

ABSTRACT

We have developed an ultrafast pulse method for protein surface footprinting by laser-induced protein surface oxidations. This method makes use of a pulse UV laser that produces, in nanoseconds, a high concentration of hydroxyl (OH) free radicals by photodissociation of a hydrogen peroxide (H2O2) solution. The OH radicals oxidize amino acid residues located on the protein surface to produce stable covalent modifications. The oxidized protein is then analyzed by mass spectrometry to map the oxidized amino acid residues. Ubiquitin and apomyoglobin were used as model proteins in this study. Our results show that a single laser pulse can produce extensive protein surface oxidations. We found that monooxidized ubiquitins were more susceptible to further oxidations by subsequent laser irradiation, as compared to nonoxidized ones. This is due to the conformational changes of proteins by oxidation that increases the solvent-accessible surface area. Therefore, it is crucial to perform this experiment with a single pulse of laser so as to avoid oxidation of proteins after conformation of the protein changes. Subsequently, to obtain a high frequency and coverage of the oxidation sites while keeping the number of laser shots to one, we further optimized the laser power and concentration of hydrogen peroxide as well as the concentration of protein. This ultrafast OH radical generation method allows for rapid and accurate detection of surface residues, enabling mapping of the solvent-accessible regions of a protein in its native state.


Subject(s)
Lasers , Mass Spectrometry/methods , Ubiquitin/chemistry , Amino Acid Sequence , Circular Dichroism , Molecular Sequence Data , Oxidation-Reduction , Photochemistry , Surface Properties , Time Factors
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