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1.
Sci Transl Med ; 10(441)2018 05 16.
Article in English | MEDLINE | ID: mdl-29769289

ABSTRACT

Metastasis remains a leading cause of cancer mortality due to the lack of specific inhibitors against this complex process. To identify compounds selectively targeting the metastatic state, we used the perinucleolar compartment (PNC), a complex nuclear structure associated with metastatic behaviors of cancer cells, as a phenotypic marker for a high-content screen of over 140,000 structurally diverse compounds. Metarrestin, obtained through optimization of a screening hit, disassembles PNCs in multiple cancer cell lines, inhibits invasion in vitro, suppresses metastatic development in three mouse models of human cancer, and extends survival of mice in a metastatic pancreatic cancer xenograft model with no organ toxicity or discernable adverse effects. Metarrestin disrupts the nucleolar structure and inhibits RNA polymerase (Pol) I transcription, at least in part by interacting with the translation elongation factor eEF1A2. Thus, metarrestin represents a potential therapeutic approach for the treatment of metastatic cancer.


Subject(s)
Cell Nucleolus/pathology , Neoplasm Metastasis/drug therapy , Pyrimidines/therapeutic use , Pyrroles/therapeutic use , Animals , Cell Line, Tumor , Cell Nucleolus/drug effects , Cell Nucleolus/metabolism , Cell Nucleolus/ultrastructure , Cell Proliferation/drug effects , Chromatin/metabolism , DNA, Ribosomal/genetics , Humans , Male , Mice , Neoplasm Invasiveness , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/pathology , Peptide Elongation Factor 1/metabolism , Promoter Regions, Genetic/genetics , Pyrimidines/chemistry , Pyrimidines/pharmacology , Pyrroles/chemistry , Pyrroles/pharmacology , RNA Polymerase I/metabolism , RNA Precursors/biosynthesis , Survival Analysis , Transcription, Genetic/drug effects , Xenograft Model Antitumor Assays
2.
J Biol Chem ; 292(10): 4302-4312, 2017 03 10.
Article in English | MEDLINE | ID: mdl-28154170

ABSTRACT

Transforming growth factor-ß (TGF-ß) signals through both SMAD and non-SMAD pathways to elicit a wide array of biological effects. Existing data have shown the association and coordination between STATs and SMADs in mediating TGF-ß functions in hepatic cells, but it is not clear how STATs are activated under these circumstances. Here, we report that JAK1 is a constitutive TGFßRI binding protein and is absolutely required for phosphorylation of STATs in a SMAD-independent manner within minutes of TGF-ß stimulation. Following the activation of SMADs, TGF-ß also induces a second phase of STAT phosphorylation that requires SMADs, de novo protein synthesis, and contribution from JAK1. Our global gene expression profiling indicates that the non-SMAD JAK1/STAT pathway is essential for the expression of a subset of TGF-ß target genes in hepatic stellate cells, and the cooperation between the JAK1-STAT3 and SMAD pathways is critical to the roles of TGF-ß in liver fibrosis.


Subject(s)
Embryo, Mammalian/pathology , Hepatic Stellate Cells/pathology , Janus Kinase 1/metabolism , Liver Cirrhosis/pathology , STAT3 Transcription Factor/metabolism , Smad Proteins/physiology , Transforming Growth Factor beta/pharmacology , Animals , Cells, Cultured , Embryo, Mammalian/drug effects , Embryo, Mammalian/metabolism , Gene Expression Profiling , Gene Expression Regulation/drug effects , Hepatic Stellate Cells/drug effects , Hepatic Stellate Cells/metabolism , Janus Kinase 1/genetics , Liver Cirrhosis/drug therapy , Liver Cirrhosis/metabolism , Mice , Mice, Knockout , Phosphorylation/drug effects , STAT3 Transcription Factor/genetics , Signal Transduction/drug effects
3.
Infect Immun ; 84(9): 2463-72, 2016 09.
Article in English | MEDLINE | ID: mdl-27297394

ABSTRACT

Immune modulation is a hallmark of patent filarial infection, including suppression of antigen-presenting cell function and downmodulation of filarial antigen-specific T cell responses. The mammalian target of rapamycin (mTOR) signaling pathway has been implicated in immune regulation, not only by suppressing T cell responses but also by regulating autophagy (through mTOR sensing amino acid availability). Global proteomic analysis (liquid chromatography-tandem mass spectrometry) of microfilaria (mf)-exposed monocyte-derived dendritic cells (DC) indicated that multiple components of the mTOR signaling pathway, including mTOR, eIF4A, and eIF4E, are downregulated by mf, suggesting that mf target this pathway for immune modulation in DC. Utilizing Western blot analysis, we demonstrate that similar to rapamycin (a known mTOR inhibitor), mf downregulate the phosphorylation of mTOR and its regulatory proteins, p70S6K1 and 4E-BP1, a process essential for DC protein synthesis. As active mTOR signaling regulates autophagy, we examined whether mf exposure alters autophagy-associated processes. mf-induced autophagy was reflected in marked upregulation of phosphorylated Beclin 1, known to play an important role in both autophagosome formation and autolysosome fusion, in induction of LC3II, a marker of autophagosome formation, and in induced degradation of p62, a ubiquitin-binding protein that aggregates protein in autophagosomes and is degraded upon autophagy that was reduced significantly by mf exposure and by rapamycin. Together, these results suggest that Brugia malayi mf employ mechanisms of metabolic modulation in DC to influence the regulation of the host immune response by downregulating mTOR signaling, resulting in increased autophagy. Whether this is a result of the parasite-secreted rapamycin homolog is currently under study.


Subject(s)
Autophagy/physiology , Brugia malayi/parasitology , Dendritic Cells/parasitology , Microfilariae/physiology , TOR Serine-Threonine Kinases/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Animals , Apoptosis Regulatory Proteins/metabolism , Autophagosomes/metabolism , Autophagosomes/parasitology , Beclin-1/metabolism , Cell Cycle Proteins , Dendritic Cells/metabolism , Down-Regulation/physiology , Eukaryotic Initiation Factor-4A/metabolism , Eukaryotic Initiation Factor-4E/metabolism , Humans , Lysosomes/metabolism , Lysosomes/parasitology , Monocytes/metabolism , Monocytes/parasitology , Phosphoproteins/metabolism , Phosphorylation/physiology , Proteomics/methods , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , Signal Transduction/physiology , Ubiquitin/metabolism , Up-Regulation/physiology
4.
Mol Cell ; 61(5): 747-759, 2016 Mar 03.
Article in English | MEDLINE | ID: mdl-26942678

ABSTRACT

Erh1, the fission yeast homolog of Enhancer of rudimentary, is implicated in meiotic mRNA elimination during vegetative growth, but its function is poorly understood. We show that Erh1 and the RNA-binding protein Mmi1 form a stoichiometric complex, called the Erh1-Mmi1 complex (EMC), to promote meiotic mRNA decay and facultative heterochromatin assembly. To perform these functions, EMC associates with two distinct complexes, Mtl1-Red1 core (MTREC) and CCR4-NOT. Whereas MTREC facilitates assembly of heterochromatin islands coating meiotic genes silenced by the nuclear exosome, CCR4-NOT promotes RNAi-dependent heterochromatin domain (HOOD) formation at EMC-target loci. CCR4-NOT also assembles HOODs at retrotransposons and regulated genes containing cryptic introns. We find that CCR4-NOT facilitates HOOD assembly through its association with the conserved Pir2/ARS2 protein, and also maintains rDNA integrity and silencing by promoting heterochromatin formation. Our results reveal connections among Erh1, CCR4-NOT, Pir2/ARS2, and RNAi, which target heterochromatin to regulate gene expression and protect genome integrity.


Subject(s)
Carrier Proteins/metabolism , Chromatin Assembly and Disassembly , Heterochromatin/metabolism , Meiosis , RNA Interference , RNA Stability , RNA, Fungal/metabolism , RNA, Messenger/metabolism , Schizosaccharomyces pombe Proteins/metabolism , Schizosaccharomyces/metabolism , mRNA Cleavage and Polyadenylation Factors/metabolism , Carrier Proteins/genetics , DNA, Ribosomal/genetics , DNA, Ribosomal/metabolism , Gene Expression Regulation, Fungal , Heterochromatin/genetics , Mutation , Nucleic Acid Conformation , Protein Binding , RNA, Fungal/genetics , RNA, Messenger/genetics , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Retroelements , Schizosaccharomyces/genetics , Schizosaccharomyces/growth & development , Schizosaccharomyces pombe Proteins/genetics , Transcription Factors/genetics , Transcription Factors/metabolism , mRNA Cleavage and Polyadenylation Factors/genetics
5.
mBio ; 7(1): e02132-15, 2016 Feb 16.
Article in English | MEDLINE | ID: mdl-26884435

ABSTRACT

UNLABELLED: Immunoassays are currently needed to quantify Loa loa microfilariae (mf). To address this need, we have conducted proteomic and bioinformatic analyses of proteins present in the urine of a Loa mf-infected patient and used this information to identify putative biomarkers produced by L. loa mf. In total, 70 of the 15,444 described putative L. loa proteins were identified. Of these 70, 18 were L. loa mf specific, and 2 of these 18 (LOAG_16297 and LOAG_17808) were biologically immunogenic. We developed novel reverse luciferase immunoprecipitation system (LIPS) immunoassays to quantify these 2 proteins in individual plasma samples. Levels of these 2 proteins in microfilaremic L. loa-infected patients were positively correlated to mf densities in the corresponding blood samples (r = 0.71 and P < 0.0001 for LOAG_16297 and r = 0.61 and P = 0.0002 for LOAG_17808). For LOAG_16297, the levels in plasma were significantly higher in Loa-infected (geometric mean [GM], 0.045 µg/ml) than in uninfected (P < 0.0001), Wuchereria bancrofti-infected (P = 0.0005), and Onchocerca volvulus-infected (P < 0.0001) individuals, whereas for LOAG_17808 protein, they were not significantly different between Loa-infected (GM, 0.123 µg/ml) and uninfected (P = 0.06) and W. bancrofti-infected (P = 0.32) individuals. Moreover, only LOAG_16297 showed clear discriminative ability between L. loa and the other potentially coendemic filariae. Indeed, the specificity of the LOAG_16297 reverse LIPS assay was 96% (with a sensitivity of 77%). Thus, LOAG_16297 is a very promising biomarker that will be exploited in a quantitative point-of-care immunoassay for determination of L. loa mf densities. IMPORTANCE: Loa loa, the causative agent of loiasis, is a parasitic nematode transmitted to humans by the tabanid Chrysops fly. Some individuals infected with L. loa microfilariae (mf) in high densities are known to experience post-ivermectin severe adverse events (SAEs [encephalopathy, coma, or death]). Thus, ivermectin-based mass drug administration (MDA) programs for onchocerciasis and for lymphatic filariasis control have been interrupted in parts of Africa where these filarial infections coexist with L. loa. To allow for implementation of MDA for onchocerciasis and lymphatic filariasis, tools that can accurately identify people at risk of developing post-ivermectin SAEs are needed. Our study, using host-based proteomics in combination with novel immunoassays, identified a single Loa-specific antigen (LOAG_16297) that can be used as a biomarker for the prediction of L. loa mf levels in the blood of infected patients. Therefore, the use of such biomarker could be important in the point-of-care assessment of L. loa mf densities.


Subject(s)
Antigens, Helminth/blood , Biomarkers/blood , Loa/immunology , Loa/isolation & purification , Loiasis/diagnosis , Loiasis/parasitology , Africa , Animals , Antigens, Helminth/immunology , Biomarkers/urine , Computational Biology , Gene Expression Profiling , Helminth Proteins/blood , Helminth Proteins/immunology , Humans , Immunoassay , Immunoprecipitation , Loiasis/immunology , Loiasis/urine , Microfilariae/immunology , Microfilariae/isolation & purification , Parasite Load , Point-of-Care Systems , Proteomics , Sensitivity and Specificity
6.
Sci Rep ; 5: 15916, 2015 Nov 02.
Article in English | MEDLINE | ID: mdl-26522388

ABSTRACT

Prenylated proteins play key roles in several human diseases including cancer, atherosclerosis and Alzheimer's disease. KRAS4b, which is frequently mutated in pancreatic, colon and lung cancers, is processed by farnesylation, proteolytic cleavage and carboxymethylation at the C-terminus. Plasma membrane localization of KRAS4b requires this processing as does KRAS4b-dependent RAF kinase activation. Previous attempts to produce modified KRAS have relied on protein engineering approaches or in vitro farnesylation of bacterially expressed KRAS protein. The proteins produced by these methods do not accurately replicate the mature KRAS protein found in mammalian cells and the protein yield is typically low. We describe a protocol that yields 5-10 mg/L highly purified, farnesylated, and methylated KRAS4b from insect cells. Farnesylated and methylated KRAS4b is fully active in hydrolyzing GTP, binds RAF-RBD on lipid Nanodiscs and interacts with the known farnesyl-binding protein PDEδ.


Subject(s)
Lipids/physiology , Protein Prenylation/physiology , Proto-Oncogene Proteins p21(ras)/metabolism , Animals , Biophysics/methods , Cell Membrane/metabolism , Cells, Cultured , Guanosine Triphosphate/metabolism , Humans , Insecta/metabolism , Methylation , Protein Binding/physiology , raf Kinases/metabolism
7.
PLoS Negl Trop Dis ; 9(9): e0004054, 2015.
Article in English | MEDLINE | ID: mdl-26367142

ABSTRACT

Filarial worms are parasitic nematodes that cause devastating diseases such as lymphatic filariasis (LF) and onchocerciasis. Filariae are nematodes with complex anatomy including fully developed digestive tracts and reproductive organs. To better understand the basic biology of filarial parasites and to provide insights into drug targets and vaccine design, we conducted a proteomic analysis of different anatomic fractions of Brugia malayi, a causative agent of LF. Approximately 500 adult female B. malayi worms were dissected, and three anatomical fractions (body wall, digestive tract, and reproductive tract) were obtained. Proteins from each anatomical fraction were extracted, desalted, trypsinized, and analyzed by microcapillary reverse-phase liquid chromatography-tandem-mass spectrometry. In total, we identified 4,785 B. malayi proteins. While 1,894 were identified in all three anatomic fractions, 396 were positively identified only within the digestive tract, 114 only within the body wall, and 1,011 only within the reproductive tract. Gene set enrichment analysis revealed a bias for transporters to be present within the digestive tract, suggesting that the intestine of adult filariae is functional and important for nutrient uptake or waste removal. As expected, the body wall exhibited increased frequencies of cytoskeletal proteins, and the reproductive tract had increased frequencies of proteins involved in nuclear regulation and transcription. In assessing for possible vaccine candidates, we focused on proteins sequestered within the digestive tract, as these could possibly represent "hidden antigens" with low risk of prior allergic sensitization. We identified 106 proteins that are enriched in the digestive tract and are predicted to localize to the surface of cells in the the digestive tract. It is possible that some of these proteins are on the luminal surface and may be accessible by antibodies ingested by the worm. A subset of 27 of these proteins appear especially promising vaccine candidates as they contain significant non-cytoplasmic domains, only 1-2 transmembrane domains, and a high degree of homology to W. bancrofti and/or O. volvulus.


Subject(s)
Brugia malayi/chemistry , Proteome/analysis , Animals , Chromatography, Liquid , Female , Gastrointestinal Tract/chemistry , Genitalia/chemistry , Proteomics , Tandem Mass Spectrometry
8.
J Immunol ; 194(8): 3594-600, 2015 Apr 15.
Article in English | MEDLINE | ID: mdl-25754738

ABSTRACT

The expression level of HLA class-I proteins is known to influence pathological outcomes: pathogens downregulate HLA to evade host immune responses, host inflammatory reactions upregulate HLA, and differences among people with regard to the steady-state expression levels of HLA associate with disease susceptibility. Yet precise quantification of relative expression levels of the various HLA loci is difficult because of the tremendous polymorphism of HLA. We report relative expression levels of HLA-A, HLA-B, HLA-C, and HLA-E proteins for the specific haplotype A*02:01, B*44:02, C*05:01, which were characterized using two independent methods based on flow cytometry and mass spectrometry. PBLs from normal donors showed that HLA-A and HLA-B proteins are expressed at similar levels, which are 13-18 times higher than HLA-C by flow cytometry and 4-5 times higher than HLA-C by mass spectrometry; these differences may reflect variation in the conformation or location of proteins detected. HLA-E was detected at a level 25 times lower than that of HLA-C by mass spectrometry. Primary CD4(+) T cells infected with HIV in vitro were also studied because HIV downregulates selective HLA types. HLA-A and HLA-B were reduced on HIV-infected cells by a magnitude that varied between cells in an infected culture. Averaging all infected cells from an individual showed HLA-A to be 1-3 times higher and HLA-B to be 2-5 times higher than HLA-C by flow cytometry. These results quantify substantial differences in expression levels of the proteins from different HLA loci, which are very likely physiologically significant on both uninfected and HIV-infected cells.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , Gene Expression Regulation/immunology , Genetic Loci/immunology , HIV Infections/immunology , Histocompatibility Antigens Class I/immunology , CD4-Positive T-Lymphocytes/pathology , Female , Flow Cytometry , HIV Infections/pathology , Humans , Male
9.
Cell ; 159(6): 1389-403, 2014 Dec 04.
Article in English | MEDLINE | ID: mdl-25467444

ABSTRACT

Telomere maintenance by telomerase is impaired in the stem cell disease dyskeratosis congenita and during human aging. Telomerase depends upon a complex pathway for enzyme assembly, localization in Cajal bodies, and association with telomeres. Here, we identify the chaperonin CCT/TRiC as a critical regulator of telomerase trafficking using a high-content genome-wide siRNA screen in human cells for factors required for Cajal body localization. We find that TRiC is required for folding the telomerase cofactor TCAB1, which controls trafficking of telomerase and small Cajal body RNAs (scaRNAs). Depletion of TRiC causes loss of TCAB1 protein, mislocalization of telomerase and scaRNAs to nucleoli, and failure of telomere elongation. DC patient-derived mutations in TCAB1 impair folding by TRiC, disrupting telomerase function and leading to severe disease. Our findings establish a critical role for TRiC-mediated protein folding in the telomerase pathway and link proteostasis, telomere maintenance, and human disease.


Subject(s)
Chaperonin Containing TCP-1/metabolism , Telomerase/metabolism , Telomere/metabolism , Dyskeratosis Congenita/genetics , Dyskeratosis Congenita/pathology , Humans , In Situ Hybridization, Fluorescence , Molecular Chaperones , Protein Folding , Telomerase/chemistry
10.
Methods Mol Biol ; 1002: 181-93, 2013.
Article in English | MEDLINE | ID: mdl-23625404

ABSTRACT

Phosphorylation has long been accepted as a key cellular regulator of cell signaling pathways. The recent development of multiple-reaction monitoring mass spectrometry (MRM-MS) provides a useful tool for measuring the absolute quantity of phosphorylation occupancy at pivotal sites within signaling proteins, even when the phosphorylation sites are in close proximity. Here, we described a targeted quantitation approach to measure the absolute phosphorylation occupancy at Y1234 and Y1235 of Met. The approach is utilized to obtain absolute occupancy of the two phosphorylation sites in the full-length recombinant Met. It is further applied to quantitate the phosphorylation state of these two sites in SNU-5 cells treated with a Met inhibitor.


Subject(s)
Mass Spectrometry , Proto-Oncogene Proteins c-met/metabolism , Tyrosine/metabolism , Humans , Phosphorylation , Proteomics , Proto-Oncogene Proteins c-met/genetics , Tyrosine/analysis , Tyrosine/chemistry
11.
Mol Cell Biol ; 32(10): 1928-43, 2012 May.
Article in English | MEDLINE | ID: mdl-22431515

ABSTRACT

The nuclear hormone receptor estrogen receptor α (ERα) mediates the actions of estrogens in target cells and is a master regulator of the gene expression and proliferative programs of breast cancer cells. The presence of ERα in breast cancer cells is crucial for the effectiveness of endocrine therapies, and its loss is a hallmark of endocrine-insensitive breast tumors. However, the molecular mechanisms underlying the regulation of the cellular levels of ERα are not fully understood. Our findings reveal a unique cellular pathway involving the p38 mitogen-activated protein kinase (p38MAPK)-mediated phosphorylation of ERα at Ser-294 that specifies its turnover by the SCF(Skp2) proteasome complex. Consistently, we observed an inverse relationship between ERα and Skp2 or active p38MAPK in breast cancer cell lines and human tumors. ERα regulation by Skp2 was cell cycle stage dependent and critical for promoting the mitogenic effects of estradiol via ERα. Interestingly, by the knockdown of Skp2 or the inhibition of p38MAPK, we restored functional ERα protein levels and the control of gene expression and proliferation by estrogen and antiestrogen in ERα-negative breast cancer cells. Our findings highlight a novel pathway with therapeutic potential for restoring ERα and the responsiveness to endocrine therapy in some endocrine-insensitive ERα-negative breast cancers.


Subject(s)
Estrogen Receptor alpha/metabolism , Proteasome Endopeptidase Complex/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism , Breast Neoplasms/drug therapy , Breast Neoplasms/metabolism , Cell Line, Tumor , Female , Humans , Molecular Targeted Therapy , Neoplasms, Hormone-Dependent/drug therapy , Neoplasms, Hormone-Dependent/metabolism , Phosphorylation , S-Phase Kinase-Associated Proteins/metabolism
12.
Proc Natl Acad Sci U S A ; 108(23): 9649-54, 2011 Jun 07.
Article in English | MEDLINE | ID: mdl-21606368

ABSTRACT

Global proteomic analyses of pathogens have thus far been limited to unicellular organisms (e.g., protozoa and bacteria). Proteomic analyses of most eukaryotic pathogens (e.g., helminths) have been restricted to specific organs, specific stages, or secretomes. We report here a large-scale proteomic characterization of almost all the major mammalian stages of Brugia malayi, a causative agent of lymphatic filariasis, resulting in the identification of more than 62% of the products predicted from the Bm draft genome. The analysis also yielded much of the proteome of Wolbachia, the obligate endosymbiont of Bm that also expressed proteins in a stage-specific manner. Of the 11,610 predicted Bm gene products, 7,103 were definitively identified from adult male, adult female, blood-borne and uterine microfilariae, and infective L3 larvae. Among the 4,956 gene products (42.5%) inferred from the genome as "hypothetical," the present study was able to confirm 2,336 (47.1%) as bona fide proteins. Analysis of protein families and domains coupled with stage-specific expression highlight the important pathways that benefit the parasite during its development in the host. Gene set enrichment analysis identified extracellular matrix proteins and those with immunologic effects as enriched in the microfilarial and L3 stages. Parasite sex- and stage-specific protein expression identified those pathways related to parasite differentiation and demonstrates stage-specific expression by the Bm endosymbiont Wolbachia as well.


Subject(s)
Bacterial Proteins/analysis , Brugia malayi/metabolism , Helminth Proteins/analysis , Proteome/analysis , Proteomics/methods , Wolbachia/metabolism , Animals , Bacterial Proteins/classification , Brugia malayi/growth & development , Brugia malayi/microbiology , Chromatography, Liquid/methods , Cluster Analysis , Female , Filariasis/parasitology , Helminth Proteins/classification , Host-Pathogen Interactions , Humans , Larva/growth & development , Larva/metabolism , Larva/microbiology , Life Cycle Stages , Male , Proteome/classification , Symbiosis , Tandem Mass Spectrometry , Wolbachia/physiology
13.
J Proteomics ; 74(12): 2650-9, 2011 Nov 18.
Article in English | MEDLINE | ID: mdl-21540133

ABSTRACT

The search for protein biomarkers has been a highly pursued topic in the proteomics community in the last decade. This relentless search is due to the constant need for validated biomarkers that could facilitate disease risk stratification, disease diagnosis, prognosis, monitoring as well as drug development, which ultimately would improve our quality of life. The recent development of proteomic technologies including the advancement of mass spectrometers with high sensitivity and speed has greatly advanced the discovery of potential biomarkers. One of the bottlenecks lies in the development of well-established verification assays to screen the biomarker candidates identified in the discovery stage. Recently, absolute quantitation using multiple-reaction monitoring mass spectrometry (MRM-MS) in combination with isotope-labeled internal standards has been extensively investigated as a tool for high-throughput protein biomarker verification. In this review, we describe and discuss recent developments and applications of MRM-MS methods for biomarker verification.


Subject(s)
Biomarkers/metabolism , Drug Design , Mass Spectrometry/methods , Proteome/metabolism , Proteomics/methods , Animals , Biomarkers/analysis , Humans , Proteome/analysis
14.
BMC Genomics ; 12: 136, 2011 Mar 01.
Article in English | MEDLINE | ID: mdl-21362191

ABSTRACT

BACKGROUND: Ticks--vectors of medical and veterinary importance--are themselves also significant pests. Tick salivary proteins are the result of adaptation to blood feeding and contain inhibitors of blood clotting, platelet aggregation, and angiogenesis, as well as vasodilators and immunomodulators. A previous analysis of the sialotranscriptome (from the Greek sialo, saliva) of Amblyomma variegatum is revisited in light of recent advances in tick sialomes and provides a database to perform a proteomic study. RESULTS: The clusterized data set has been expertly curated in light of recent reviews on tick salivary proteins, identifying many new families of tick-exclusive proteins. A proteome study using salivary gland homogenates identified 19 putative secreted proteins within a total of 211 matches. CONCLUSIONS: The annotated sialome of A. variegatum allows its comparison to other tick sialomes, helping to consolidate an emerging pattern in the salivary composition of metastriate ticks; novel protein families were also identified. Because most of these proteins have no known function, the task of functional analysis of these proteins and the discovery of novel pharmacologically active compounds becomes possible.


Subject(s)
Gene Expression Profiling , Ixodidae/genetics , Proteome/genetics , Salivary Proteins and Peptides/genetics , Amino Acid Sequence , Animals , Chromatography, Liquid , Computational Biology , Databases, Protein , Female , Gene Library , Molecular Sequence Data , Tandem Mass Spectrometry
15.
J Proteome Res ; 10(2): 669-79, 2011 Feb 04.
Article in English | MEDLINE | ID: mdl-21058630

ABSTRACT

Dipetalogaster maxima is a blood-sucking Hemiptera that inhabits sylvatic areas in Mexico. It usually takes its blood meal from lizards, but following human population growth, it invaded suburban areas, feeding also on humans and domestic animals. Hematophagous insect salivary glands produce potent pharmacologic compounds that counteract host hemostasis, including anticlotting, antiplatelet, and vasodilatory molecules. To obtain further insight into the salivary biochemical and pharmacologic complexity of this insect, a cDNA library from its salivary glands was randomly sequenced. Salivary proteins were also submitted to one- and two-dimensional gel electrophoresis (1DE and 2DE) followed by mass spectrometry analysis. We present the analysis of a set of 2728 cDNA sequences, 1375 of which coded for proteins of a putative secretory nature. The saliva 2DE proteome displayed approximately 150 spots. The mass spectrometry analysis revealed mainly lipocalins, pallidipins, antigen 5-like proteins, and apyrases. The redundancy of sequence identification of saliva-secreted proteins suggests that proteins are present in multiple isoforms or derive from gene duplications.


Subject(s)
Insect Proteins/analysis , Proteome/analysis , Triatominae/metabolism , Amino Acid Sequence , Animals , Cluster Analysis , Electrophoresis, Polyacrylamide Gel , Gene Expression Profiling , Gene Library , Insect Proteins/classification , Insect Proteins/metabolism , Mass Spectrometry , Molecular Sequence Data , Peptide Mapping , Proteome/metabolism , RNA, Messenger/chemistry , RNA, Messenger/isolation & purification , Salivary Glands/chemistry , Salivary Glands/metabolism , Sequence Alignment
16.
J Proteomics ; 73(1): 112-22, 2009 Nov 02.
Article in English | MEDLINE | ID: mdl-19709643

ABSTRACT

Proteomic profiling of membrane proteins is of vital importance in the search for disease biomarkers and drug development. However, the slow pace in this field has resulted mainly from the difficulty to analyze membrane proteins by mass spectrometry (MS). The objective of this investigation was to explore and optimize solubilization of membrane proteins for shotgun membrane proteomics of the CD14 human monocytes by examining different systems that rely on: i) an organic solvent (methanol) ii) an acid-labile detergent 3-[3-(1,1-bisalkyloxyethyl)pyridin-1-yl]propane-1-sulfonate (PPS), iii) a combination of both agents (methanol+PPS). Solubilization efficiency of different buffers was first compared using bacteriorhodopsin as a model membrane protein. Selected approaches were then applied on a membrane subproteome isolated from a highly enriched human monocyte population that was approximately 98% positive for CD14 expression as determined by FACS analysis. A methanol-based buffer yielded 194 proteins of which 93 (48%) were mapped as integral membrane proteins. The combination of methanol and acid-cleavable detergent gave similar results; 203 identified proteins of which 93 (46%) were mapped integral membrane proteins. However, employing PPS 216 proteins were identified of which 75 (35%) were mapped as integral membrane proteins. These results indicate that methanol alone or in combination with PPS yielded significantly higher membrane protein identification/enrichment than the PPS alone.


Subject(s)
Lipopolysaccharide Receptors/analysis , Membrane Proteins/isolation & purification , Membrane Proteins/metabolism , Monocytes/metabolism , Proteomics/methods , Tandem Mass Spectrometry/methods , Bacteriorhodopsins/chemistry , Bacteriorhodopsins/metabolism , Calibration , Caseins/metabolism , Chromatography, Liquid/methods , Humans , Hydrophobic and Hydrophilic Interactions , Lipopolysaccharide Receptors/chemistry , Membrane Proteins/chemistry , Monocytes/chemistry , Protein Hydrolysates/metabolism , Proteome/analysis , Proteome/chemistry , Proteomics/standards , Solubility
17.
Nature ; 460(7251): 66-72, 2009 Jul 02.
Article in English | MEDLINE | ID: mdl-19571879

ABSTRACT

Stem cells are controlled, in part, by genetic pathways frequently dysregulated during human tumorigenesis. Either stimulation of Wnt/beta-catenin signalling or overexpression of telomerase is sufficient to activate quiescent epidermal stem cells in vivo, although the mechanisms by which telomerase exerts these effects are not understood. Here we show that telomerase directly modulates Wnt/beta-catenin signalling by serving as a cofactor in a beta-catenin transcriptional complex. The telomerase protein component TERT (telomerase reverse transcriptase) interacts with BRG1 (also called SMARCA4), a SWI/SNF-related chromatin remodelling protein, and activates Wnt-dependent reporters in cultured cells and in vivo. TERT serves an essential role in formation of the anterior-posterior axis in Xenopus laevis embryos, and this defect in Wnt signalling manifests as homeotic transformations in the vertebrae of Tert(-/-) mice. Chromatin immunoprecipitation of the endogenous TERT protein from mouse gastrointestinal tract shows that TERT physically occupies gene promoters of Wnt-dependent genes. These data reveal an unanticipated role for telomerase as a transcriptional modulator of the Wnt/beta-catenin signalling pathway.


Subject(s)
Chromatin/genetics , Signal Transduction , Telomerase/metabolism , Wnt Proteins/metabolism , Animals , Cell Line , Choristoma/genetics , Choristoma/pathology , DNA Helicases/metabolism , Genes, Reporter/genetics , HeLa Cells , Humans , Intestine, Small/metabolism , Mice , Nuclear Proteins/metabolism , Oocytes/cytology , Oocytes/growth & development , Plasmids/genetics , Promoter Regions, Genetic/genetics , Somites/abnormalities , Somites/embryology , Transcription Factors/metabolism , Wnt Proteins/genetics , Wnt3 Protein , Xenopus laevis/embryology , beta Catenin/genetics
18.
PLoS Negl Trop Dis ; 3(4): e410, 2009.
Article in English | MEDLINE | ID: mdl-19352421

ABSTRACT

Relatively little is known about the filarial proteins that interact with the human host. Although the filarial genome has recently been completed, protein profiles have been limited to only a few recombinants or purified proteins of interest. Here, we describe a large-scale proteomic analysis using microcapillary reverse-phase liquid chromatography-tandem-mass spectrometry to identify the excretory-secretory (ES) products of the L3, L3 to L4 molting ES, adult male, adult female, and microfilarial stages of the filarial parasite Brugia malayi. The analysis of the ES products from adult male, adult female, microfilariae (Mf), L3, and molting L3 larvae identified 852 proteins. Annotation suggests that the functional and component distribution was very similar across each of the stages studied; however, the Mf contributed a higher proportion to the total number of identified proteins than the other stages. Of the 852 proteins identified in the ES, only 229 had previous confirmatory expressed sequence tags (ESTs) in the available databases. Moreover, this analysis was able to confirm the presence of 274 "hypothetical" proteins inferred from gene prediction algorithms applied to the B. malayi (Bm) genome. Not surprisingly, the majority (160/274) of these "hypothetical" proteins were predicted to be secreted by Signal IP and/or SecretomeP 2.0 analysis. Of major interest is the abundance of previously characterized immunomodulatory proteins such as ES-62 (leucyl aminopeptidase), MIF-1, SERPIN, glutathione peroxidase, and galectin in the ES of microfilariae (and Mf-containing adult females) compared to the adult males. In addition, searching the ES protein spectra against the Wolbachia database resulted in the identification of 90 Wolbachia-specific proteins, most of which were metabolic enzymes that have not been shown to be immunogenic. This proteomic analysis extends our knowledge of the ES and provides insight into the host-parasite interaction.


Subject(s)
Brugia malayi/chemistry , Brugia malayi/growth & development , Helminth Proteins/metabolism , Host-Pathogen Interactions , Proteome/analysis , Animals , Chromatography, Liquid , Erythrocytes , Female , Male , Mass Spectrometry
19.
Nature ; 458(7234): 92-6, 2009 Mar 05.
Article in English | MEDLINE | ID: mdl-19118383

ABSTRACT

The transcription factor NF-kappaB is required for lymphocyte activation and proliferation as well as the survival of certain lymphoma types. Antigen receptor stimulation assembles an NF-kappaB activating platform containing the scaffold protein CARMA1 (also called CARD11), the adaptor BCL10 and the paracaspase MALT1 (the CBM complex), linked to the inhibitor of NF-kappaB kinase complex, but signal transduction is not fully understood. We conducted parallel screens involving a mass spectrometry analysis of CARMA1 binding partners and an RNA interference screen for growth inhibition of the CBM-dependent 'activated B-cell-like' (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). Here we report that both screens identified casein kinase 1alpha (CK1alpha) as a bifunctional regulator of NF-kappaB. CK1alpha dynamically associates with the CBM complex on T-cell-receptor (TCR) engagement to participate in cytokine production and lymphocyte proliferation. However, CK1alpha kinase activity has a contrasting role by subsequently promoting the phosphorylation and inactivation of CARMA1. CK1alpha has thus a dual 'gating' function which first promotes and then terminates receptor-induced NF-kappaB. ABC DLBCL cells required CK1alpha for constitutive NF-kappaB activity, indicating that CK1alpha functions as a conditionally essential malignancy gene-a member of a new class of potential cancer therapeutic targets.


Subject(s)
Casein Kinases/metabolism , Lymphoma, Large B-Cell, Diffuse/metabolism , Lymphoma, Large B-Cell, Diffuse/pathology , NF-kappa B/metabolism , Receptors, Antigen/metabolism , Adaptor Proteins, Signal Transducing/metabolism , B-Cell CLL-Lymphoma 10 Protein , CARD Signaling Adaptor Proteins/metabolism , Caspases/metabolism , Cell Proliferation , Cell Survival , Cells, Cultured , Feedback, Physiological , Guanylate Cyclase/metabolism , Humans , I-kappa B Kinase/metabolism , Jurkat Cells , Lymphoma, Large B-Cell, Diffuse/enzymology , Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein , Neoplasm Proteins/metabolism , Protein Binding , Signal Transduction
20.
J Proteome Res ; 8(3): 1474-88, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19166301

ABSTRACT

Adaptation to vertebrate blood feeding includes development of a salivary "magic potion" that can disarm host hemostasis and inflammatory reactions. Within the lower Diptera, a vertebrate blood-sucking mode evolved in the Psychodidae (sand flies), Culicidae (mosquitoes), Ceratopogonidae (biting midges), Simuliidae (black flies), and the frog-feeding Corethrellidae. Sialotranscriptome analyses from several species of mosquitoes and sand flies and from one biting midge indicate divergence in the evolution of the blood-sucking salivary potion, manifested in the finding of many unique proteins within each insect family, and even genus. Gene duplication and divergence events are highly prevalent, possibly driven by vertebrate host immune pressure. Within this framework, we describe the sialome (from Greek sialo, saliva) of the black fly Simulium vittatum and discuss the findings within the context of the protein families found in other blood-sucking Diptera. Sequences and results of Blast searches against several protein family databases are given in Supplemental Tables S1 and S2, which can be obtained from http://exon.niaid.nih.gov/transcriptome/S_vittatum/T1/SV-tb1.zip and http://exon.niaid.nih.gov/transcriptome/S_vittatum/T2/SV-tb2.zip .


Subject(s)
Gene Library , Proteome/metabolism , Saliva/metabolism , Salivary Glands/metabolism , Simuliidae/physiology , Amino Acid Sequence , Animals , Electrophoresis, Polyacrylamide Gel , Molecular Sequence Data , Phylogeny , Tandem Mass Spectrometry
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