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Moriyama M, Hayashi T, Fukatsu T. A mucin protein predominantly expressed in the female-specific symbiotic organ of the stinkbug Plautia stali. Sci Rep 2022; 12:7782. [PMID: 35546182 PMCID: PMC9095716 DOI: 10.1038/s41598-022-11895-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/28/2022] [Indexed: 12/04/2022] Open
Abstract
Diverse insects are obligatorily associated with microbial symbionts, wherein the host often develops special symbiotic organs and vertically transmits the symbiont to the next generation. What molecular factors underpin the host-symbiont relationship is of great interest but poorly understood. Here we report a novel protein preferentially produced in a female-specific symbiotic organ of the stinkbug Plautia stali, whose posterior midgut develops numerous crypts to host a Pantoea-allied bacterial mutualist. In adult females, several posteriormost crypts are conspicuously enlarged, presumably specialized for vertical symbiont transmission. We detected conspicuous protein bands specific to the female’s swollen crypts by gel electrophoresis, and identified them as representing a novel mucin-like glycoprotein. Histological inspections confirmed that the mucin protein is localized to the female’s swollen crypts, coexisting with a substantial population of the symbiotic bacteria, and excreted from the swollen crypts to the midgut main tract together with the symbiotic bacteria. Using RNA interference, we successfully suppressed production of the mucin protein in adult females of P. stali. However, although the mucin protein was depleted, the symbiont population persisted in the swollen crypts, and vertical symbiont transmission to the next generation occurred. Possible biological roles and evolutionary trajectory of the symbiosis-related mucin protein are discussed.
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Affiliation(s)
- Minoru Moriyama
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.
| | - Toshinari Hayashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan.,Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - Takema Fukatsu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan. .,Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, 113-0033, Japan. .,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, 305-8572, Japan.
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2
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Kaulich PT, Cassidy L, Weidenbach K, Schmitz RA, Tholey A. Complementarity of Different SDS‐PAGE Gel Staining Methods for the Identification of Short Open Reading Frame‐Encoded Peptides. Proteomics 2020; 20:e2000084. [DOI: 10.1002/pmic.202000084] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/15/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Philipp T. Kaulich
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine Christian‐Albrechts‐Universität zu Kiel Kiel 24105 Germany
| | - Liam Cassidy
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine Christian‐Albrechts‐Universität zu Kiel Kiel 24105 Germany
| | - Katrin Weidenbach
- Institute for General Microbiology Christian‐Albrechts‐Universität zu Kiel Kiel 24118 Germany
| | - Ruth A. Schmitz
- Institute for General Microbiology Christian‐Albrechts‐Universität zu Kiel Kiel 24118 Germany
| | - Andreas Tholey
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine Christian‐Albrechts‐Universität zu Kiel Kiel 24105 Germany
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3
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Xie Z, Zou Z, Raz A, Qin H, Fischetti V, Zhang S, Kreth J, Merritt J. Regulatory control of the Streptococcus mutans HdrRM LytTR Regulatory System functions via a membrane sequestration mechanism. Mol Microbiol 2020; 114:681-693. [PMID: 32706915 DOI: 10.1111/mmi.14576] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 02/04/2023]
Abstract
Bacteria sense and respond to environmental changes via several broad categories of sensory signal transduction systems. Recently, we described the key features of a previously unrecognized, but widely conserved class of prokaryotic sensory system that we refer to as the LytTR Regulatory System (LRS). Our previous studies suggest that most, if not all, prokaryotic LRS membrane proteins serve as inhibitors of their cognate transcription regulators, but the inhibitory mechanisms employed have thus far remained a mystery. Using the Streptococcus mutans HdrRM LRS as a model, we demonstrate how the LRS membrane protein HdrM inhibits its cognate transcription regulator HdrR by tightly sequestering HdrR in a membrane-localized heteromeric HdrR/M complex. Membrane sequestration of HdrR prevents the positive feedback autoregulatory function of HdrR, thereby maintaining a low basal expression of the hdrRM operon. However, this mechanism can be antagonized by ectopically expressing a competitive inhibitor mutant form of HdrR that lacks its DNA binding ability while still retaining its HdrM interaction. Our results indicate that sequestration of HdrR is likely to be the only mechanism required to inhibit its transcription regulator function, suggesting that endogenous activation of the HdrRM LRS is probably achieved through a modulation of the HdrR/M interaction.
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Affiliation(s)
- Zhoujie Xie
- MOE Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Zhengzhong Zou
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - Assaf Raz
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY, USA
| | - Hua Qin
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - Vincent Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY, USA
| | - Shan Zhang
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - Jens Kreth
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA
| | - Justin Merritt
- Department of Restorative Dentistry, Oregon Health and Science University, Portland, OR, USA.,Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, USA
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4
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Wenzel CQ, Mills DC, Dobruchowska JM, Vlach J, Nothaft H, Nation P, Azadi P, Melville SB, Carlson RW, Feldman MF, Szymanski CM. An atypical lipoteichoic acid from Clostridium perfringens elicits a broadly cross-reactive and protective immune response. J Biol Chem 2020; 295:9513-9530. [PMID: 32424044 DOI: 10.1074/jbc.ra119.009978] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 05/02/2020] [Indexed: 12/14/2022] Open
Abstract
Clostridium perfringens is a leading cause of food-poisoning and causes avian necrotic enteritis, posing a significant problem to both the poultry industry and human health. No effective vaccine against C. perfringens is currently available. Using an antiserum screen of mutants generated from a C. perfringens transposon-mutant library, here we identified an immunoreactive antigen that was lost in a putative glycosyltransferase mutant, suggesting that this antigen is likely a glycoconjugate. Following injection of formalin-fixed whole cells of C. perfringens HN13 (a laboratory strain) and JGS4143 (chicken isolate) intramuscularly into chickens, the HN13-derived antiserum was cross-reactive in immunoblots with all tested 32 field isolates, whereas only 5 of 32 isolates were recognized by JGS4143-derived antiserum. The immunoreactive antigens from both HN13 and JGS4143 were isolated, and structural analysis by MALDI-TOF-MS, GC-MS, and 2D NMR revealed that both were atypical lipoteichoic acids (LTAs) with poly-(β1→4)-ManNAc backbones substituted with phosphoethanolamine. However, although the ManNAc residues in JGS4143 LTA were phosphoethanolamine-modified, a few of these residues were instead modified with phosphoglycerol in the HN13 LTA. The JGS4143 LTA also had a terminal ribose and ManNAc instead of ManN in the core region, suggesting that these differences may contribute to the broadly cross-reactive response elicited by HN13. In a passive-protection chicken experiment, oral challenge with C. perfringens JGS4143 lead to 22% survival, whereas co-gavage with JGS4143 and α-HN13 antiserum resulted in 89% survival. This serum also induced bacterial killing in opsonophagocytosis assays, suggesting that HN13 LTA is an attractive target for future vaccine-development studies.
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Affiliation(s)
- Cory Q Wenzel
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Dominic C Mills
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | | | - Jiri Vlach
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Harald Nothaft
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick Nation
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Stephen B Melville
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Russell W Carlson
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Mario F Feldman
- VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Molecular Microbiology, Washington University of Medicine, St. Louis, Missouri, USA
| | - Christine M Szymanski
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada .,VaxAlta Inc., Edmonton, Alberta, Canada.,Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada.,Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
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5
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Sono T, Akiyama H, Miura S, Deng JM, Shukunami C, Hiraki Y, Tsushima Y, Azuma Y, Behringer RR, Matsuda S. THRAP3 interacts with and inhibits the transcriptional activity of SOX9 during chondrogenesis. J Bone Miner Metab 2018; 36:410-419. [PMID: 28770354 DOI: 10.1007/s00774-017-0855-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 06/17/2017] [Indexed: 11/28/2022]
Abstract
Sex-determining region Y (Sry)-box (Sox)9 is required for chondrogenesis as a transcriptional activator of genes related to chondrocyte proliferation, differentiation, and cartilage-specific extracellular matrix. Although there have been studies investigating the Sox9-dependent transcriptional complexes, not all their components have been identified. In the present study, we demonstrated that thyroid hormone receptor-associated protein (THRAP)3 is a component of a SOX9 transcriptional complex by liquid chromatography mass spectrometric analysis of FLAG-tagged Sox9-binding proteins purified from FLAG-HA-tagged Sox9 knock-in mice. Thrap3 knockdown in ATDC5 chondrogenic cells increased the expression of Collagen type II alpha 1 chain (Col2a1) without affecting Sox9 expression. THRAP3 and SOX9 overexpression reduced Col2a1 levels to a greater degree than overexpression of SOX9 alone. The negative regulation of SOX9 transcriptional activity by THRAP3 was mediated by interaction between the proline-, glutamine-, and serine-rich domain of SOX9 and the innominate domain of THRAP3. These results indicate that THRAP3 negatively regulates SOX9 transcriptional activity as a cofactor of a SOX9 transcriptional complex during chondrogenesis.
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Affiliation(s)
- Takashi Sono
- Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Haruhiko Akiyama
- Department of Orthopaedic Surgery, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
| | - Shigenori Miura
- Laboratory of Cellular Differentiation, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Jian Min Deng
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Chisa Shukunami
- Laboratory of Cellular Differentiation, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Department of Molecular Biology and Biochemistry, Division of Basic Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Yuji Hiraki
- Laboratory of Cellular Differentiation, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yu Tsushima
- Pharmacology Research Department, Teijin Pharma Limited, Hino, Tokyo, Japan
| | - Yoshiaki Azuma
- Medical Science Department, Teijin Pharma Limited, Tokyo, Japan
| | - Richard R Behringer
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Shuichi Matsuda
- Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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6
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Kafle P, Amoh AN, Reaves JM, Suneby EG, Tutunjian KA, Tyson RL, Schneider TL. Molecular Insights into the Impact of Oxidative Stress on the Quorum-Sensing Regulator Protein LasR. J Biol Chem 2016; 291:11776-86. [PMID: 27053110 DOI: 10.1074/jbc.m116.719351] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Indexed: 01/05/2023] Open
Abstract
The LasR regulator protein functions at the top of the Pseudomonas aeruginosa quorum-sensing hierarchy and is implicated in promoting bacterial virulence. Of note is recent evidence that this transcription factor may also respond to oxidative stress. Here, all cysteines in LasR were inspected to deduce their redox sensitivity and to probe the connection between stress response and LasR activity using purified LasR and individual LasR domains. Cys(79) in the ligand binding domain of LasR appears to be important for ligand recognition and folding of this domain to potentiate DNA binding but does not seem to be sensitive to oxidative stress when bound to its native ligand. Two cysteines in the DNA binding domain of LasR do form a disulfide bond when treated with hydrogen peroxide, and formation of this Cys(201)-Cys(203) disulfide bond appears to disrupt the DNA binding activity of the transcription factor. Mutagenesis of either of these cysteines leads to expression of a protein that no longer binds DNA. A cell-based reporter assay linking LasR function with β-galactosidase activity gave results consistent with those obtained with purified LasR. This work provides a possible mechanism for oxidative stress response by LasR and indicates that multiple cysteines within the protein may prove to be useful targets for disabling its activity.
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Affiliation(s)
- Prapti Kafle
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
| | - Amanda N Amoh
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
| | - Jocelyn M Reaves
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
| | - Emma G Suneby
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
| | - Kathryn A Tutunjian
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
| | - Reed L Tyson
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
| | - Tanya L Schneider
- From the Department of Chemistry, Connecticut College, New London, Connecticut 06320
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7
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Analytical purification of a 60-kDa target protein of artemisinin detected in Trypanosoma brucei brucei. Data Brief 2016; 5:383-7. [PMID: 26958596 PMCID: PMC4773405 DOI: 10.1016/j.dib.2015.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/08/2015] [Accepted: 09/22/2015] [Indexed: 11/23/2022] Open
Abstract
Here we describe the isolation and purity determination of Trypanosoma brucei (T. b.) brucei candidate target proteins of artemisinin. The candidate target proteins were detected and purified from their biological source (T. b. brucei lysate) using the diazirine-free biotinylated probe 5 for an affinity binding to a streptavidin-tagged resin and, subsequently, the labeled target proteins were purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). We herein showed the electrophoresis gel and the immunoblotting film containing the 60-kDa trypanosomal candidate target protein of artemisinin as a single band, which was visualized on-gel by the reverse-staining method and on a Western blotting film by enhanced chemiluminescence. The data provided in this article are related to the original research article "Biotinylated probes of artemisinin with labeling affinity toward Trypanosoma brucei brucei target proteins", by Konziase (Anal. Biochem., vol. 482, 2015, pp. 25-31. http://dx.doi.org/10.1016/j.ab.2015.04.020).
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8
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Lipopolysaccharide aggregates in native agarose gels detected by reversible negative staining with imidazole and zinc salts. Anal Biochem 2015; 485:72-80. [PMID: 26095395 DOI: 10.1016/j.ab.2015.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 06/12/2015] [Accepted: 06/12/2015] [Indexed: 11/23/2022]
Abstract
We investigated the use of imidazole and zinc salts for the detection of lipopolysaccharide (LPS) aggregates separated by native agarose gel electrophoresis (NAGE). As a result, a new staining procedure was established by which as little as 1.5 μg of Escherichia coli O55:B5 LPS aggregates was detected by means of inducing a clear, transparent pattern, contrasted against an opaque background. E. coli O55:B5 LPS preparations treated with nucleases and proteinase K proved that the reverse-stained LPS pattern is not related to any potential artifacts caused by unrelated biomolecules (e.g., nucleic acids, proteins). After this, we showed that the procedure is applicable to two-dimensional LPS separation using NAGE/SDS-PAGE, while at the same time confirming that real polydisperse LPS aggregates are represented by the stained profile. Also, we demonstrated the general applicability of this stain to the detection of different NAGE-separated LPS aggregates (e.g., from E. coli 026:B6, E. coli 0111:B4, Salmonella minnesota Re595). Finally, using lysozyme as a model protein, we found that imidazole-zinc may be combined with Coomassie brilliant blue R-250 into a double-staining process to enable the use of NAGE for investigating the interaction of cationic proteins and LPS aggregates and protein or LPS concentration effects on protein-LPS binding.
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9
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Liu X, Li L, Sun J, Yan Y, Shu X, Liu B, Sha W, Feng H, Sun S, Zhu J. A coordination complex system for generic, ultrafast, and sensitive multimode fluorescent staining of biomolecules. Inorg Chem 2012; 51:188-92. [PMID: 22145885 DOI: 10.1021/ic201406b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gel electrophoresis staining methodologies documented thus far are largely utilized in a biomolecule context-dependent manner. We report herein the development of a generic, ultrafast, and sensitive multimode fluorescent system for the efficient identification of DNA, RNA, and proteins. Interaction between a positively charged, planar ligand-based coordination complex with partner biomolecule leads to aggregation-induced fluorescence quenching and allows for the image contrast generation within one minute. Alternatively, successive reactions of the biomolecule-loaded gel with cation and ligand, in either order of sequence, provide an equally effective staining efficacy. Image contrast reversal is accomplished through a facile washing or photobleaching procedure. The versatility in the applicable target species and signal generation modes provides a hint at the design of novel staining structures and potentially enables the high-throughput readout of biomolecules.
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Affiliation(s)
- Xingqiang Liu
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, China
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10
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King JG, Vernick KD, Hillyer JF. Members of the salivary gland surface protein (SGS) family are major immunogenic components of mosquito saliva. J Biol Chem 2011; 286:40824-34. [PMID: 21965675 PMCID: PMC3220476 DOI: 10.1074/jbc.m111.280552] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/23/2011] [Indexed: 11/06/2022] Open
Abstract
Mosquitoes transmit Plasmodium and certain arboviruses during blood feeding, when they are injected along with saliva. Mosquito saliva interferes with the host's hemostasis and inflammation response and influences the transmission success of some pathogens. One family of mosquito salivary gland proteins, named SGS, is composed of large bacterial-type proteins that in Aedes aegypti were implicated as receptors for Plasmodium on the basal salivary gland surface. Here, we characterize the biology of two SGSs in the malaria mosquito, Anopheles gambiae, and demonstrate their involvement in blood feeding. Western blots and RT-PCR showed that Sgs4 and Sgs5 are produced exclusively in female salivary glands, that expression increases with age and after blood feeding, and that protein levels fluctuate in a circadian manner. Immunohistochemistry showed that SGSs are present in the acinar cells of the distal lateral lobes and in the salivary ducts of the proximal lobes. SDS-PAGE, Western blots, bite blots, and immunization via mosquito bites showed that SGSs are highly immunogenic and form major components of mosquito saliva. Last, Western and bioinformatic analyses suggest that SGSs are secreted via a non-classical pathway that involves cleavage into a 300-kDa soluble fragment and a smaller membrane-bound fragment. Combined, these data strongly suggest that SGSs play an important role in blood feeding. Together with their role in malaria transmission, we propose that SGSs could be used as markers of human exposure to mosquito bites and in the development of disease control strategies.
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Affiliation(s)
- Jonas G. King
- From the Department of Biological Sciences and Institute for Global Health, Vanderbilt University, Nashville, Tennessee 37235 and
| | - Kenneth D. Vernick
- the Department of Parasitology and Mycology, Institut Pasteur, Paris 75015, France
| | - Julián F. Hillyer
- From the Department of Biological Sciences and Institute for Global Health, Vanderbilt University, Nashville, Tennessee 37235 and
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11
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Sokabe M, Fraser CS, Hershey JWB. The human translation initiation multi-factor complex promotes methionyl-tRNAi binding to the 40S ribosomal subunit. Nucleic Acids Res 2011; 40:905-13. [PMID: 21940399 PMCID: PMC3258154 DOI: 10.1093/nar/gkr772] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The delivery of Met-tRNAi to the 40S ribosomal subunit is thought to occur by way of a ternary complex (TC) comprising eIF2, GTP and Met-tRNAi. We have generated from purified human proteins a stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported in yeast and plants. A human MFC free of the ribosome also is detected in HeLa cells and rabbit reticulocytes, indicating that it exists in vivo. In vitro, the MFC-GTP binds Met-tRNAi and delivers the tRNA to the ribosome at the same rate as the TC. However, MFC-GDP shows a greatly reduced affinity to Met-tRNAi compared to that for eIF2-GDP, suggesting that MFC components may play a role in the release of eIF2-GDP from the ribosome following AUG recognition. Since an MFC–Met-tRNAi complex is detected in cell lysates, it may be responsible for Met-tRNAi–40S ribosome binding in vivo, possibly together with the TC. However, the MFC protein components also bind individually to 40S ribosomes, creating the possibility that Met-tRNAi might bind directly to such 40S-factor complexes. Thus, three distinct pathways for Met-tRNAi delivery to the 40S ribosomal subunit are identified, but which one predominates in vivo remains to be elucidated.
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Affiliation(s)
- Masaaki Sokabe
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA 95616, USA
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12
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Boonyapranai K, Tsai HY, Chen MCM, Sriyam S, Sinchaikul S, Phutrakul S, Chen ST. Glycoproteomic analysis and molecular modeling of haptoglobin multimers. Electrophoresis 2011; 32:1422-32. [PMID: 21692080 DOI: 10.1002/elps.201000464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Extra-thiol groups on the α-subunit allow haptoglobin (Hp) to form a variety of native multimers which influence the biophysical and biological properties of Hp. In this work, we demonstrated how differences of multimeric conformation alter the glycosylation of Hp. The isoform distributions of different multimers were examined by an alternative approach, i.e. 3-D-(Native/IEF/SDS)-PAGE, which revealed differences in N-glycosylation among individual multimers of the same Hp sample. Glycomic mapping of permethylated N-glycan indicated that the assembled monomer and multimeric conformation modulate the degree of glycosylation, especially the reduction in terminal sialic acid residues on the bi-antennary glycan. Loss of the terminal sialic acid in the higher order multimers increases the number of terminal galactose residues, which may contribute to conformation of Hp. A molecular model of the glycosylated Hp multimer was constructed, suggesting that the effect of steric hindrance on multimeric formation is critical for the enlargement of the glycan moieties on either side of the monomer. In addition, N241 of Hp was partially glycosylated, even though this site is unaffected by steric consideration. Thus, the present study provides evidence for the alteration of glycan structures on different multimeric conformations of Hp, improving our knowledge of conformation-dependent function of this glycoprotein.
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Affiliation(s)
- Kongsak Boonyapranai
- Institute of Biological Chemistry and Genomics Research Center, Academia Sinica, Taipei, Taiwan
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13
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Dalla Pellegrina C, Perbellini O, Scupoli MT, Tomelleri C, Zanetti C, Zoccatelli G, Fusi M, Peruffo A, Rizzi C, Chignola R. Effects of wheat germ agglutinin on human gastrointestinal epithelium: insights from an experimental model of immune/epithelial cell interaction. Toxicol Appl Pharmacol 2009; 237:146-53. [PMID: 19332085 DOI: 10.1016/j.taap.2009.03.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 03/02/2009] [Accepted: 03/21/2009] [Indexed: 01/22/2023]
Abstract
Wheat germ agglutinin (WGA) is a plant protein that binds specifically to sugars expressed, among many others, by human gastrointestinal epithelial and immune cells. WGA is a toxic compound and an anti-nutritional factor, but recent works have shown that it may have potential as an anti-tumor drug and as a carrier for oral drugs. To quantitate the toxicity threshold for WGA on normal epithelial cells we previously investigated the effects of the lectin on differentiated Caco2 cells, and showed that in the micromolar range of concentrations WGA could alter the integrity of the epithelium layer and increase its permeability to both mannitol and dextran. WGA was shown to be uptaken by Caco2 cells and only approximately 0.1% molecules were observed to cross the epithelium layer by transcytosis. Here we show that at nanomolar concentrations WGA is unexpectedly bioactive on immune cells. The supernatants of WGA-stimulated peripheral blood mononuclear cells (PBMC) can alter the integrity of the epithelium layer when administered to the basolateral side of differentiated Caco2 cells and the effects can be partially inhibited by monoclonal antibodies against IL1, IL6 and IL8. At nanomolar concentrations WGA stimulates the synthesis of pro-inflammatory cytokines and thus the biological activity of WGA should be reconsidered by taking into account the effects of WGA on the immune system at the gastrointestinal interface. These results shed new light onto the molecular mechanisms underlying the onset of gastrointestinal disorders observed in vivo upon dietary intake of wheat-based foods.
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Affiliation(s)
- Chiara Dalla Pellegrina
- Department of Biotechnology, University of Verona, Strada Le Grazie 15-CV1, I-37134 Verona, Italy
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14
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15
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Hellman J. Stabilization of thin-layer agarose gels after isoelectric focusing with polyacrylamide enables reverse imidazole-zinc staining and facilitates two-dimensional gel electrophoresis. Anal Bioanal Chem 2008; 392:239-45. [DOI: 10.1007/s00216-008-2247-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/21/2008] [Accepted: 06/12/2008] [Indexed: 11/29/2022]
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