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Alfaro-Sifuentes R, Lares-Jiménez LF, Rojas-Hernández S, Carrasco-Yépez MM, Rojas-Ortega DA, Rodriguez-Anaya LZ, Gonzalez-Galaviz JR, Lares-Villa F. Immunogens in Balamuthia mandrillaris: a proteomic exploration. Parasitol Res 2024; 123:173. [PMID: 38536506 DOI: 10.1007/s00436-024-08193-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
Balamuthia mandrillaris is the causative agent of granulomatous amoebic encephalitis, a rare and often fatal infection affecting the central nervous system. The amoeba is isolated from diverse environmental sources and can cause severe infections in both immunocompromised and immunocompetent individuals. Given the limited understanding of B. mandrillaris, our research aimed to explore its protein profile, identifying potential immunogens crucial for early granulomatous amoebic encephalitis diagnosis. Cultures of B. mandrillaris and other amoebas were grown under axenic conditions, and total amoebic extracts were obtained. Proteomic analyses, including two-dimensional electrophoresis and mass spectrometry, were performed. A 50-kDa band showed a robust recognition of antibodies from immunized BALB/c mice; peptides contained in this band were matched with elongation factor-1 alpha, which emerged as a putative key immunogen. Besides, lectin blotting revealed the presence of glycoproteins in B. mandrillaris, and confocal microscopy demonstrated the focal distribution of the 50-kDa band throughout trophozoites. Cumulatively, these observations suggest the participation of the 50-kDa band in adhesion and recognition mechanisms. Thus, these collective findings demonstrate some protein characteristics of B. mandrillaris, opening avenues for understanding its pathogenicity and developing diagnostic and therapeutic strategies.
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Affiliation(s)
- Rosalía Alfaro-Sifuentes
- Programa de Doctorado en Ciencias Especialidad en Biotecnología, Departamento de Biotecnología y Ciencias Alimentarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
| | - Luis Fernando Lares-Jiménez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México
| | - Saul Rojas-Hernández
- Laboratorio de Inmunología Molecular, Instituto Politécnico Nacional, Escuela Superior de Medicina, Salvador Díaz Mirón Esq. Plan de San Luis S/N, Miguel Hidalgo, Casco de Santo Tomas, Ciudad de México, México
| | | | - Diego Alexander Rojas-Ortega
- Centro de Investigación en Ciencias de La Salud (CICSA), FCS, Universidad Anáhuac México, 52786, Huixquilucan, Estado de México, México
| | | | | | - Fernando Lares-Villa
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
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Sadhukhan A, Agrahari RK, Wu L, Watanabe T, Nakano Y, Panda SK, Koyama H, Kobayashi Y. Expression genome-wide association study identifies that phosphatidylinositol-derived signalling regulates ALUMINIUM SENSITIVE3 expression under aluminium stress in the shoots of Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 302:110711. [PMID: 33288018 DOI: 10.1016/j.plantsci.2020.110711] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 10/02/2020] [Accepted: 10/04/2020] [Indexed: 06/12/2023]
Abstract
To identify unknown regulatory mechanisms leading to aluminium (Al)-induction of the Al tolerance gene ALS3, we conducted an expression genome-wide association study (eGWAS) for ALS3 in the shoots of 95 Arabidopsis thaliana accessions in the presence of Al. The eGWAS was conducted using a mixed linear model with 145,940 genome-wide single nucleotide polymorphisms (SNPs) and the association results were validated using reverse genetics. We found that many SNPs from the eGWAS were associated with genes related to phosphatidylinositol metabolism as well as stress signal transduction, including Ca2+signals, inter-connected in a co-expression network. Of these, PLC9, CDPK32, ANAC071, DIR1, and a hypothetical protein (AT4G10470) possessed amino acid sequence/ gene expression level polymorphisms that were significantly associated with ALS3 expression level variation. Furthermore, T-DNA insertion mutants of PLC9, CDPK32, and ANAC071 suppressed shoot ALS3 expression in the presence of Al. This study clarified the regulatory mechanisms of ALS3 expression in the shoot and provided genetic evidence of the involvement of phosphatidylinositol-derived signal transduction under Al stress.
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Affiliation(s)
- Ayan Sadhukhan
- Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan
| | - Raj Kishan Agrahari
- Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan
| | - Liujie Wu
- Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan
| | - Toshihiro Watanabe
- Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kitaku, Sapporo, 060-8589, Japan
| | - Yuki Nakano
- Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan
| | - Sanjib Kumar Panda
- Department of Biochemistry, Central University of Rajasthan, Rajasthan 305817, India
| | - Hiroyuki Koyama
- Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan
| | - Yuriko Kobayashi
- Applied Biological Sciences, Gifu University, Yanagido 1-1, Gifu, Gifu 501-1193, Japan.
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Carriles AA, Mills A, Muñoz-Alonso MJ, Gutiérrez D, Domínguez JM, Hermoso JA, Gago F. Structural Cues for Understanding eEF1A2 Moonlighting. Chembiochem 2020; 22:374-391. [PMID: 32875694 DOI: 10.1002/cbic.202000516] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/01/2020] [Indexed: 12/16/2022]
Abstract
Spontaneous mutations in the EEF1A2 gene cause epilepsy and severe neurological disabilities in children. The crystal structure of eEF1A2 protein purified from rabbit skeletal muscle reveals a post-translationally modified dimer that provides information about the sites of interaction with numerous binding partners, including itself, and maps these mutations onto the dimer and tetramer interfaces. The spatial locations of the side chain carboxylates of Glu301 and Glu374, to which phosphatidylethanolamine is uniquely attached via an amide bond, define the anchoring points of eEF1A2 to cellular membranes and interorganellar membrane contact sites. Additional bioinformatic and molecular modeling results provide novel structural insight into the demonstrated binding of eEF1A2 to SH3 domains, the common MAPK docking groove, filamentous actin, and phosphatidylinositol-4 kinase IIIβ. In this new light, the role of eEF1A2 as an ancient, multifaceted, and articulated G protein at the crossroads of autophagy, oncogenesis and viral replication appears very distant from the "canonical" one of delivering aminoacyl-tRNAs to the ribosome that has dominated the scene and much of the thinking for many decades.
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Affiliation(s)
- Alejandra A Carriles
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry "Rocasolano" CSIC, 28006, Madrid, Spain.,Biocrystallography Unit, Division of Immunology, Transplantation, and Infectious Diseases, IRCCS Scientific Institute San Raffaele, 20132, Milan, Italy
| | - Alberto Mills
- Department of Biomedical Sciences and "Unidad Asociada IQM-CSIC", School of Medicine and Health Sciences, University of Alcalá, 28805, Alcalá de Henares, Madrid, Spain
| | - María-José Muñoz-Alonso
- Department of Cell Biology and Pharmacogenomics, PharmaMar S.A.U., 28770, Colmenar Viejo, Madrid, Spain
| | - Dolores Gutiérrez
- Proteomics Unit, Faculty of Pharmacy, Complutense University, 28040, Madrid, Spain
| | - Juan M Domínguez
- Department of Cell Biology and Pharmacogenomics, PharmaMar S.A.U., 28770, Colmenar Viejo, Madrid, Spain
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Institute of Physical-Chemistry "Rocasolano" CSIC, 28006, Madrid, Spain
| | - Federico Gago
- Department of Biomedical Sciences and "Unidad Asociada IQM-CSIC", School of Medicine and Health Sciences, University of Alcalá, 28805, Alcalá de Henares, Madrid, Spain
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Evaluation on Elongation Factor 1 Alpha of Entamoeba histolytica Interaction with the Intermediate Subunit of the Gal/GalNAc Lectin and Actin in Phagocytosis. Pathogens 2020; 9:pathogens9090702. [PMID: 32867020 PMCID: PMC7558290 DOI: 10.3390/pathogens9090702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 11/17/2022] Open
Abstract
Entamoeba histolytica is the causative agent of amoebiasis. This disease results in 40,000 to 100,000 deaths annually. The pathogenic molecules involved in the invasion of trophozoites had been constantly being clarified. This study explored the role of elongation factor 1 alpha (EF1a) in E. histolytica pathogenicity. Biolayer interferometry binding and pull-down assays suggest that EF1a and intermediate subunit of lectin (Igl) binding are specific. Submembranous distribution of EF1a closely aligns with the localization of Igl, which appear in abundance on membranes of trophozoites. Messenger RNA (mRNA) expression of EF1a is positively correlated with trends in Igl levels after co-incubation with Chinese hamster ovary (CHO) cells in vitro, suggesting a regulatory linkage between these proteins. Erythrophagocytosis assays also imply a role for EF1a in phagocytosis. Finally, EF1a and actin are collocated in trophozoites. These results indicated elongation factor 1a is associated with E. histolytica phagocytosis, and the relationships between EF1a, Igl, and actin are worth further study to better understand the pathogenic process.
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Ermert AL, Mailliet K, Hughes J. Holophytochrome-Interacting Proteins in Physcomitrella: Putative Actors in Phytochrome Cytoplasmic Signaling. FRONTIERS IN PLANT SCIENCE 2016; 7:613. [PMID: 27242820 PMCID: PMC4867686 DOI: 10.3389/fpls.2016.00613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 04/21/2016] [Indexed: 05/26/2023]
Abstract
Phytochromes are the principle photoreceptors in light-regulated plant development, primarily acting via translocation of the light-activated photoreceptor into the nucleus and subsequent gene regulation. However, several independent lines of evidence indicate unambiguously that an additional cytoplasmic signaling mechanism must exist. Directional responses in filament tip cells of the moss Physcomitrella patens are steered by phy4 which has been shown to interact physically with the blue light receptor phototropin at the plasma membrane. This complex might perceive and transduce vectorial information leading to cytoskeleton reorganization and finally a directional growth response. We developed yeast two-hybrid procedures using photochemically functional, full-length phy4 as bait in Physcomitrella cDNA library screens and growth assays under different light conditions, revealing Pfr-dependent interactions possibly associated with phytochrome cytoplasmic signaling. Candidate proteins were then expressed in planta with fluorescent protein tags to determine their intracellular localization in darkness and red light. Of 14 candidates, 12 were confirmed to interact with phy4 in planta using bimolecular fluorescence complementation. We also used database information to study their expression patterns relative to those of phy4. We discuss the likely functional characteristics of these holophytochrome-interacting proteins (HIP's) and their possible roles in signaling.
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Transcriptome profiling of differentially expressed genes in floral buds and flowers of male sterile and fertile lines in watermelon. BMC Genomics 2015; 16:914. [PMID: 26552448 PMCID: PMC4640349 DOI: 10.1186/s12864-015-2186-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 11/02/2015] [Indexed: 12/03/2022] Open
Abstract
Background Male sterility is an important mechanism for the production of hybrid seeds in watermelon. Although fruit development has been studied extensively in watermelon, there are no reports on gene expression in floral organs. In this study, RNA-sequencing (RNA-seq) was performed in two near-isogenic watermelon lines (genic male sterile [GMS] line, DAH3615-MS and male fertile line, DAH3615) to identify the differentially expressed genes (DEGs) related to male sterility. Results DEG analysis showed that 1259 genes were significantly associated with male sterility at a FDR P-value of < 0.01. Most of these genes were only expressed in the male fertile line. In addition, 11 functional clusters were identified using DAVID functional classification analysis. Of detected genes in RNA-seq analysis, 19 were successfully validated by qRT-PCR. Conclusions In this study, we carried out a comprehensive floral transcriptome sequence comparison of a male fertile line and its near-isogenic male sterile line in watermelon. This analysis revealed essential genes responsible for stamen development, including pollen development and pollen tube elongation, and allowed their functional classification. These results provided new information on global mechanisms related to male sterility in watermelon. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2186-9) contains supplementary material, which is available to authorized users.
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Na I, Reddy KD, Breydo L, Xue B, Uversky VN. A putative role of the Sup35p C-terminal domain in the cytoskeleton organization during yeast mitosis. ACTA ACUST UNITED AC 2014; 10:925-40. [DOI: 10.1039/c3mb70515c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Based on structural analysis of several effectors and partners, Sup35pC is proposed to serve as actin modulator during mitosis.
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Affiliation(s)
- Insung Na
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
| | - Krishna D. Reddy
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
| | - Leonid Breydo
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
| | - Bin Xue
- Department of Cell Biology
- Microbiology, and Molecular Biology
- College of Arts and Science
- University of South Florida
- Tampa, USA
| | - Vladimir N. Uversky
- Department of Molecular Medicine
- Morsani College of Medicine
- University of South Florida
- Tampa, USA
- USF Health Byrd Alzheimer's Research Institute
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Ischebeck T, Valledor L, Lyon D, Gingl S, Nagler M, Meijón M, Egelhofer V, Weckwerth W. Comprehensive cell-specific protein analysis in early and late pollen development from diploid microsporocytes to pollen tube growth. Mol Cell Proteomics 2014; 13:295-310. [PMID: 24078888 PMCID: PMC3879621 DOI: 10.1074/mcp.m113.028100] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 09/24/2013] [Indexed: 01/10/2023] Open
Abstract
Pollen development in angiosperms is one of the most important processes controlling plant reproduction and thus productivity. At the same time, pollen development is highly sensitive to environmental fluctuations, including temperature, drought, and nutrition. Therefore, pollen biology is a major focus in applied studies and breeding approaches for improving plant productivity in a globally changing climate. The most accessible developmental stages of pollen are the mature pollen and the pollen tubes, and these are thus most frequently analyzed. To reveal a complete quantitative proteome map, we additionally addressed the very early stages, analyzing eight stages of tobacco pollen development: diploid microsporocytes, meiosis, tetrads, microspores, polarized microspores, bipolar pollen, desiccated pollen, and pollen tubes. A protocol for the isolation of the early stages was established. Proteins were extracted and analyzed by means of a new gel LC-MS fractionation protocol. In total, 3817 protein groups were identified. Quantitative analysis was performed based on peptide count. Exceedingly stage-specific differential protein regulation was observed during the conversion from the sporophytic to the gametophytic proteome. A map of highly specialized functionality for the different stages could be revealed from the metabolic activity and pronounced differentiation of proteasomal and ribosomal protein complex composition up to protective mechanisms such as high levels of heat shock proteins in the very early stages of development.
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Affiliation(s)
- Till Ischebeck
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Luis Valledor
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - David Lyon
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Stephanie Gingl
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Matthias Nagler
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Mónica Meijón
- ¶Gregor-Mendel-Institute for Molecular Plant Biology, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Volker Egelhofer
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
| | - Wolfram Weckwerth
- From the ‡Department of Molecular Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, A-1090, Vienna, Austria
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Abstract
"All things flow and change…even in the stillest matter there is unseen flux and movement." Attributed to Heraclitus (530-470 BC), from The Story of Philosophy by Will Durant. Heraclitus, a Greek philosopher, was thinking on a much larger scale than molecular signaling; however, his visionary comments are an important reminder for those studying signaling today. Even in unstimulated cells, signaling pathways are in constant metabolic flux and provide basal signals that travel throughout the organism. In addition, negatively charged phospholipids, such as the polyphosphorylated inositol phospholipids, provide a circuit board of on/off switches for attracting or repelling proteins that define the membranes of the cell. This template of charged phospholipids is sensitive to discrete changes and metabolic fluxes-e.g., in pH and cations-which contribute to the oscillating signals in the cell. The inherent complexities of a constantly fluctuating system make understanding how plants integrate and process signals challenging. In this review we discuss one aspect of lipid signaling: the inositol family of negatively charged phospholipids and their functions as molecular sensors and regulators of metabolic flux in plants.
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Affiliation(s)
- Wendy F Boss
- Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7649, USA.
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10
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Hamrita B, Nasr HB, Hammann P, Kuhn L, Guillier CL, Chaieb A, Khairi H, Chahed K. An elongation factor-like protein (EF-Tu) elicits a humoral response in infiltrating ductal breast carcinomas: An immunoproteomics investigation. Clin Biochem 2011; 44:1097-1104. [DOI: 10.1016/j.clinbiochem.2011.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/30/2011] [Accepted: 06/01/2011] [Indexed: 10/18/2022]
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Pinke DE, Lee JM. The lipid kinase PI4KIIIβ and the eEF1A2 oncogene co-operate to disrupt three-dimensional in vitro acinar morphogenesis. Exp Cell Res 2011; 317:2503-11. [PMID: 21851817 DOI: 10.1016/j.yexcr.2011.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 07/29/2011] [Accepted: 08/01/2011] [Indexed: 11/25/2022]
Abstract
The study of in vitro morphogenesis is fundamental to understanding neoplasia since the dysregulation of morphogenic pathways that create multi-cellular organisms is a common hallmark of oncogenesis. The in vitro culture of human breast epithelial cells on reconstituted basement membranes recapitulate some features of in vivo breast development, including the formation of a three-dimensional structure termed an acinus. Importantly, the capacity to disrupt in vitro acinar morphogenesis is a common property of human breast oncogenes. In this report, we find that phosphatidylinositol 4-kinase IIIβ (PI4KIIIβ), a lipid kinase that phosphorylates phosphatidylinositol (PI) to PI(4)P, disrupts in vitro mammary acinar formation. The PI4KIIIβ protein localizes to the basal surface of acini created by human MCF10A cells and ectopic expression of PI4KIIIβ induces multi-acinar devlopment. Furthermore, expression of an oncogenic PI4KIIIβ activator, eEF1A2 (eukaryotic elongation factor 1 alpha 2), phenocopies the PI4KIIIβ multi-acinar phenotype. Ectopic expression of PI4KIIIβ or eEF1A2 alters the localization of PI(4)P and PI(4,5)P(2) within acini, indicating the importance of these lipids in acinar development. Our work shows that PI4KIIIβ, eEF1A2 and PI(4)P likely play an important role in mammary neoplasia and acinar development.
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Affiliation(s)
- Dixie E Pinke
- Department of Biochemistry, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
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Krupyanko VI. Perspectives of data analysis of enzyme inhibition and activation, part 4: equations for calculation of constants of enzyme activation and inhibition. J Biochem Mol Toxicol 2010; 24:145-54. [PMID: 20583219 DOI: 10.1002/jbt.20316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Equations for calculation of constants of enzyme activation and nontrivial types of enzyme inhibition, which are not reported in the literature, have been deduced. Examples of using these equations are also presented.
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Affiliation(s)
- Vladimir I Krupyanko
- G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Prospect Nauki 5, Moscow region, 142290, Russia.
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Wang C, Zhou J, Wang S, Ye M, Jiang C, Fan G, Zou H. Combined Comparative and Chemical Proteomics on the Mechanisms of levo-Tetrahydropalmatine-Induced Antinociception in the Formalin Test. J Proteome Res 2010; 9:3225-34. [DOI: 10.1021/pr1001274] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Chen Wang
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
| | - Jiangrui Zhou
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
| | - Shuowen Wang
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
| | - Mingliang Ye
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
| | - Chunlei Jiang
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
| | - Guorong Fan
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
| | - Hanfa Zou
- Department of Pharmaceutical Analysis, School of Pharmacy, Second Military Medical University, No.325 Guohe Road, Shanghai 200433, People's Republic of China, Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, No.457 Zhongshan Road, Dalian 116023, People's Republic of China, Laboratory of Stress Medicine, Department of Nautical Medicine, Second Military Medical University, No.800 Xiangyin Road, Shanghai 200433, People's Republic of China, and Shanghai Key Laboratory for Pharmaceutical
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Zhong D, Zhang J, Yang S, Soh UJK, Buschdorf JP, Zhou YT, Yang D, Low BC. The SAM domain of the RhoGAP DLC1 binds EF1A1 to regulate cell migration. J Cell Sci 2009; 122:414-24. [PMID: 19158340 DOI: 10.1242/jcs.027482] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Deleted in liver cancer 1 (DLC1) is a multi-modular Rho-GTPase-activating protein (RhoGAP) and a tumor suppressor. Besides its RhoGAP domain, functions of other domains in DLC1 remain largely unknown. By protein precipitation and mass spectrometry, we identified eukaryotic elongation factor 1A1 (EF1A1) as a novel partner for the sterile alpha motif (SAM) domain of DLC1 but not the SAM domain of DLC2. The solution structure of DLC1 SAM revealed a new monomeric fold with four parallel helices, similar to that of DLC2 SAM but distinct from other SAM domains. Mutating F38, L39 and F40 within a hydrophobic patch retained its overall structure but abolished its interaction with EF1A1 with F38 and L39 forming an indispensable interacting motif. DLC1 SAM did not localize to and was not required for DLC1 to suppress the turnover of focal adhesions. Instead, DLC1 SAM facilitated EF1A1 distribution to the membrane periphery and ruffles upon growth factor stimulation. Compared with wild-type DLC1, the non-interactive DLC1 mutant is less potent in suppressing cell migration, whereas overexpression of the DLC1 SAM domain alone, but not the non-interactive mutant SAM or DLC2 SAM, greatly enhanced cell migration. This finding reveals a novel contribution of the SAM-EF1A1 interaction as a potentially important GAP-independent modulation of cell migration by DLC1.
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Affiliation(s)
- Dandan Zhong
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
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15
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Ransom-Hodgkins WD. The application of expression analysis in elucidating the eukaryotic elongation factor one alpha gene family in Arabidopsis thaliana. Mol Genet Genomics 2009; 281:391-405. [PMID: 19132394 DOI: 10.1007/s00438-008-0418-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
Eukaryotic elongation factor one alpha (eEF1A) encoding genes are part of the large GTP binding protein family. The eEF1A family is important for protein synthesis and actin filament and bundle formation. In this study, the expression of four eEF1A genes in Arabidopsis thaliana is reported. Microarray analyses of the gene family showed high expression levels in germinating seeds, embryos, and shoot and root meristems. Quantitative real time RT-PCR was used to determine individual eEF1A gene expression. Unlike animals, in Arabidopsis tissues all four eEF1A genes were expressed in all tissues sampled. However, the abundance of each transcript varied spatially. Knocking out expression of one eEF1A gene produced seedlings with stunted roots and a subsequent change in expression of the other three eEF1A genes. The varying abundance of each gene in different tissues may indicate different concentration requirements for each message product. These results will be very useful for elucidating the role of each gene in growth, development, and stress responses of the plant.
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Affiliation(s)
- Wendy Danielle Ransom-Hodgkins
- Department of Biological Sciences, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5410, USA.
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16
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Leclercq TM, Moretti PAB, Vadas MA, Pitson SM. Eukaryotic elongation factor 1A interacts with sphingosine kinase and directly enhances its catalytic activity. J Biol Chem 2008; 283:9606-14. [PMID: 18263879 PMCID: PMC2442288 DOI: 10.1074/jbc.m708782200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 01/23/2008] [Indexed: 01/07/2023] Open
Abstract
Sphingosine 1-phosphate (S1P) has many important roles in mammalian cells, including contributing to the control of cell survival and proliferation. S1P is generated by sphingosine kinases (SKs), of which two mammalian isoforms have been identified (SK1 and SK2). To gain a better understanding of SK regulation, we have used a yeast two-hybrid screen to identify SK1-interacting proteins and established elongation factor 1A (eEF1A) as one such protein that associates with both SK1 and SK2. We show the direct interaction of eEF1A with the SKs in vitro, whereas the physiological relevance of this association was demonstrated by co-immunoprecipitation of the endogenous proteins from cell lysates. Although the canonical role of eEF1A resides in protein synthesis, it has also been implicated in other roles, including regulating the activity of some signaling enzymes. Thus, we examined the potential role of eEF1A in regulation of the SKs and show that eEF1A is able to directly increase the activity of SK1 and SK2 approximately 3-fold in vitro. Substrate kinetics demonstrated that eEF1A increased the catalytic rate of both SKs, while having no observable effect on substrate affinities of these enzymes for either ATP or sphingosine. Overexpression of eEF1A in quiescent Chinese hamster ovary cells increased cellular SK activity, whereas a small interfering RNA-mediated decrease in eEF1A levels in MCF7 cells substantially reduced cellular SK activity and S1P levels, supporting the in vivo physiological relevance of this interaction. Thus, this study has established a novel mechanism of regulation of both SK1 and SK2 that is mediated by their interaction with eEF1A.
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Affiliation(s)
- Tamara M Leclercq
- Hanson Institute, Division of Human Immunology, Institute of Medical and Veterinary Science, Frome Road, Adelaide, South Australia 5000, Australia
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17
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Infante C, Asensio E, Cañavate JP, Manchado M. Molecular characterization and expression analysis of five different elongation factor 1 alpha genes in the flatfish Senegalese sole (Solea senegalensis Kaup): differential gene expression and thyroid hormones dependence during metamorphosis. BMC Mol Biol 2008; 9:19. [PMID: 18234081 PMCID: PMC2270864 DOI: 10.1186/1471-2199-9-19] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Accepted: 01/30/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Eukaryotic elongation factor 1 alpha (eEF1A) is one of the four subunits composing eukaryotic translation elongation factor 1. It catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome in a GTP-dependent manner during protein synthesis, although it also seems to play a role in other non-translational processes. Currently, little information is still available about its expression profile and regulation during flatfish metamorphosis. With regard to this, Senegalese sole (Solea senegalensis) is a commercially important flatfish in which eEF1A gene remains to be characterized. RESULTS The development of large-scale genomics of Senegalese sole has facilitated the identification of five different eEF1A genes, referred to as SseEF1A1, SseEF1A2, SseEF1A3, SseEF1A4, and Sse42Sp50. Main characteristics and sequence identities with other fish and mammalian eEF1As are described. Phylogenetic and tissue expression analyses allowed for the identification of SseEF1A1 and SseEF1A2 as the Senegalese sole counterparts of mammalian eEF1A1 and eEF1A2, respectively, and of Sse42Sp50 as the ortholog of Xenopus laevis and teleost 42Sp50 gene. The other two elongation factors, SseEF1A3 and SseEF1A4, represent novel genes that are mainly expressed in gills and skin. The expression profile of the five genes was also studied during larval development, revealing different behaviours. To study the possible regulation of SseEF1A gene expressions by thyroid hormones (THs), larvae were exposed to the goitrogen thiourea (TU). TU-treated larvae exhibited lower SseEF1A4 mRNA levels than untreated controls at both 11 and 15 days after treatment, whereas transcripts of the other four genes remained relatively unchanged. Moreover, addition of exogenous T4 hormone to TU-treated larvae increased significantly the steady-state levels of SseEF1A4 with respect to untreated controls, demonstrating that its expression is up-regulated by THs. CONCLUSION We have identified five different eEF1A genes in the Senegalese sole, referred to as SseEF1A1, SseEF1A2, SseEF1A3, SseEF1A4, and Sse42Sp50. The five genes exhibit different expression patterns in tissues and during larval development. TU and T4 treatments demonstrate that SseEF1A4 is up-regulated by THs, suggesting a role in the translational regulation of the factors involved in the dramatic changes that occurs during Senegalese sole metamorphosis.
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Affiliation(s)
- Carlos Infante
- IFAPA Centro El Toruño, Junta de Andalucía, Camino Tiro de pichón s/n, 11500 El Puerto de Santa María, Cádiz, Spain.
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18
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Lopez M, Cherkasov A, Nandan D. Molecular architecture of leishmania EF-1α reveals a novel site that may modulate protein translation: A possible target for drug development. Biochem Biophys Res Commun 2007; 356:886-92. [PMID: 17397800 DOI: 10.1016/j.bbrc.2007.03.077] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 03/09/2007] [Indexed: 11/29/2022]
Abstract
Elongation factor-1alpha plays an essential role in eukaryotic protein biosynthesis. Recently, we have shown by protein structure modeling the presence of a hairpin-loop of 12 amino acids in mammalian EF-1alpha that is absent in the leishmania homologue [D. Nandan, A. Cherkasov, R. Sabouti, T. Yi, N.E. Reiner, Molecular cloning, biochemical and structural analysis of elongation factor-1 alpha from Leishmania donovani: comparison with the mammalian homologue, Biochem. Biophys. Res. Commun. 302 (2003) 646-652]. As a consequence of this deletion, an exposed region is available on the main body of leishmania EF-1alpha. Here we report the generation of an anti-EF-1alpha antibody (DN-3) which bound selectively to the exposed region of leishmania EF-1alpha, with no reactivity with human EF-1alpha. In a leishmania cell-free protein translation system, DN-3 substantially inhibited protein translation. A similar inhibitory effect was observed when a specific peptide based on the exposed region was used in the cell-free protein translation assay. The application of structure-based in silico methods to identify potential ligands to target the exposed region identified a small molecule that selectively attenuated in vitro translation using leishmania extracts. Moreover, this small molecule showed selective suppressive effect on multiplication of leishmania in culture. Taken together, these findings identify a novel, exposed region in leishmania EF-1alpha that may be involved in protein synthesis and a potential site for drug targeting.
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Affiliation(s)
- Martin Lopez
- Department of Medicine (Division of Infectious Diseases), University of British Columbia, Faculties of Medicine and Science, 2733 Heather Street, Heather Pavilion East, Room 452-D, Vancouver, BC, Canada V5Z 3J5
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19
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Boss WF, Davis AJ, Im YJ, Galvão RM, Perera IY. Phosphoinositide metabolism: towards an understanding of subcellular signaling. Subcell Biochem 2006; 39:181-205. [PMID: 17121276 DOI: 10.1007/0-387-27600-9_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Wendy F Boss
- Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7612, USA
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20
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Jeganathan S, Lee JM. Binding of elongation factor eEF1A2 to phosphatidylinositol 4-kinase beta stimulates lipid kinase activity and phosphatidylinositol 4-phosphate generation. J Biol Chem 2006; 282:372-80. [PMID: 17088255 DOI: 10.1074/jbc.m602955200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Eukaryotic protein translation elongation factor 1 alpha 2 (eEF1A2) is an oncogene that transforms mammalian cell lines and increases their tumorigenicity in nude mice. Increased expression of eEF1A2 occurs during the development of breast, ovarian, and lung cancer. Here, we report that eEF1A2 directly binds to and activates phosphatidylinositol 4-kinase III beta (PI4KIIIbeta), an enzyme that converts phosphatidylinositol to phosphatidylinositol 4-phosphate. Purified recombinant eEF1A2 increases PI4KIIIbeta lipid kinase activity in vitro, and expression of eEF1A2 in rat and human cells is sufficient to increase overall cellular phosphatidylinositol 4-kinase activity and intracellular phosphatidylinositol 4-phosphate abundance. siRNA-mediated reduction in eEF1A2 expression concomitantly reduces phosphatidylinositol 4-kinase activity. This identifies a physical and functional relationship between eEF1A2 and PI4KIIIbeta.
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Affiliation(s)
- Sujeeve Jeganathan
- Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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21
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Pogribna AP, Negrutskii BS, Elskaya AV. Removal of part of the eEF1A GTP binding domain induced translation errors in vitro. ACTA ACUST UNITED AC 2006. [DOI: 10.7124/bc.00072f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- A. P. Pogribna
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - B. S. Negrutskii
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
| | - A. V. Elskaya
- Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine
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22
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Mansilla F, Hansen LL, Jakobsen H, Kjeldgaard NO, Clark BFC, Knudsen CR. Deconstructing PTI-1: PTI-1 is a truncated, but not mutated, form of translation elongatin factor 1A1, eEF1A1. ACTA ACUST UNITED AC 2005; 1727:116-24. [PMID: 15716006 DOI: 10.1016/j.bbaexp.2004.12.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 12/15/2004] [Accepted: 12/16/2004] [Indexed: 11/30/2022]
Abstract
The prostate tumor-inducing gene 1 (PTI-1) transcript is detected in various human carcinoma cells. PTI-1 is reported to consist of a 5' untranslated region (5' UTR) homologous to mycoplasma 23S rRNA and a coding region corresponding to a truncated and mutated form of the translation elongation factor 1A, eEF1A. We have found that the PTI-1 transcript may encode a truncated, but not mutated, form of the human isoform eEF1A1. Additionally, the 5' UTR sequence of PTI-1 from genomic DNA of different cell lines and blood samples varies from the original sequence. This 5' -UTR region of PTI-1 presents a fusion of E. coli and Mycoplasma hyorhinis 23S rRNA. We have overexpressed the potential PTI-1 protein in E. coli and various human cell lines. The resulting protein could be detected by western blotting using anti-eEF1A antibodies. However, we were unable to detect the PTI-1 protein in LNCaP cell extracts. The potential roles of the PTI-1 protein in carcinogenesis and the origin of the PTI-1 gene in the human genome are discussed.
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Affiliation(s)
- Francisco Mansilla
- Department of Molecular Biology, University of Aarhus, Arhus C, Denmark.
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23
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Nandan D, Reiner NE. Leishmania donovani engages in regulatory interference by targeting macrophage protein tyrosine phosphatase SHP-1. Clin Immunol 2005; 114:266-77. [PMID: 15721837 DOI: 10.1016/j.clim.2004.07.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 07/22/2004] [Indexed: 11/21/2022]
Abstract
Protozoan parasites of the genus leishmania are obligate intracellular parasites of monocytes and macrophages. These pathogens have evolved to invade the mammalian immune system and typically survive for long periods of time. Leishmania have developed a variety of remarkable strategies to prevent their elimination by both innate and acquired immune effector mechanisms. One particular strategy of interest involves manipulation of host cell regulatory pathways so as to prevent macrophage activation required for efficient microbicidal activity. These interference mechanisms are the main focus of this review. Several lines of evidence have been developed to show that the Src homology-2 domain containing tyrosine phosphatase-1 (SHP-1) becomes activated in leishmania-infected cells and that this contributes to disease pathogenesis. Recent studies aimed at understanding the mechanism responsible for the change in activation state of SHP-1 led to the identification of leishmania EF-1alpha as an SHP-1 binding protein and SHP-1 activator. This was a surprising finding given that this ubiquitous and highly conserved protein plays an essential role in protein translation in both prokaryotic and eukaryotic cells. The role of leishmania EF-1alpha as an SHP-1 activator and its contribution to pathogenesis are reviewed with particular attention to the properties that distinguish it from host EF-1alpha.
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Affiliation(s)
- Devki Nandan
- Division of Infectious Diseases, Department of Medicine, Vancouver Coastal Health Research Institute (VCHRI), The University of British Columbia, Room 452D, 2733 Heather Street, Vancouver, BC, Canada, V5Z 3J5.
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24
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Mongrand S, Morel J, Laroche J, Claverol S, Carde JP, Hartmann MA, Bonneu M, Simon-Plas F, Lessire R, Bessoule JJ. Lipid rafts in higher plant cells: purification and characterization of Triton X-100-insoluble microdomains from tobacco plasma membrane. J Biol Chem 2004; 279:36277-86. [PMID: 15190066 DOI: 10.1074/jbc.m403440200] [Citation(s) in RCA: 385] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A large body of evidence from the past decade supports the existence of functional microdomains in membranes of animal and yeast cells, which play important roles in protein sorting, signal transduction, or infection by pathogens. They are based on the dynamic clustering of sphingolipids and cholesterol or ergosterol and are characterized by their insolubility, at low temperature, in nonionic detergents. Here we show that similar microdomains also exist in plant plasma membrane isolated from both tobacco leaves and BY2 cells. Tobacco lipid rafts were found to be greatly enriched in a sphingolipid, identified as glycosylceramide, as well as in a mixture of stigmasterol, sitosterol, 24-methylcholesterol, and cholesterol. Phospho- and glycoglycerolipids of the plasma membrane were largely excluded from lipid rafts. Membrane proteins were separated by one- and two-dimensional gel electrophoresis and identified by tandem mass spectrometry or use of specific antibody. The data clearly indicate that tobacco microdomains are able to recruit a specific set of the plasma membrane proteins and exclude others. We demonstrate the recruitment of the NADPH oxidase after elicitation by cryptogein and the presence of the small G protein NtRac5, a negative regulator of NADPH oxidase, in lipid rafts.
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MESH Headings
- Blotting, Western
- Cell Membrane/metabolism
- Centrifugation, Density Gradient
- Cholesterol/analogs & derivatives
- Cholesterol/metabolism
- Chromatography, High Pressure Liquid
- Chromatography, Thin Layer
- Detergents/pharmacology
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Ergosterol/metabolism
- Ions
- Lipid Metabolism
- Lipids/chemistry
- Mass Spectrometry
- Membrane Microdomains/chemistry
- Membrane Microdomains/metabolism
- Microscopy, Electron
- NADPH Oxidases/metabolism
- Octoxynol/pharmacology
- Phytosterols
- Plant Leaves/metabolism
- Protein Structure, Tertiary
- Signal Transduction
- Sitosterols/metabolism
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Stigmasterol/metabolism
- Sucrose/pharmacology
- Temperature
- Nicotiana/metabolism
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Affiliation(s)
- Sébastien Mongrand
- Laboratoire de Biogenèse Membranaire, FRE 2694-CNRS-Université Victor Segalen Bordeaux 2, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France.
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25
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Lopez-Valenzuela JA, Gibbon BC, Hughes PA, Dreher TW, Larkins BA. eEF1A isoforms change in abundance and actin-binding activity during maize endosperm development. PLANT PHYSIOLOGY 2003; 133:1285-95. [PMID: 14526107 PMCID: PMC281623 DOI: 10.1104/pp.103.027854] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2003] [Revised: 07/07/2003] [Accepted: 07/27/2003] [Indexed: 05/20/2023]
Abstract
Eukaryotic elongation factor 1A (eEF1A) appears to be a multifunctional protein because several biochemical activities have been described for this protein, in addition to its role in protein synthesis. In maize (Zea mays) endosperm, the synthesis of eEF1A is increased in o2 (opaque2) mutants, and its concentration is highly correlated with the protein-bound lysine content. To understand the basis of this relationship, we purified eEF1A isoforms from developing endosperm and investigated their accumulation and their functional and structural properties. Formation of three isoforms appears to be developmentally regulated and independent of the o2 mutation, although one isoform predominated in one high lysine o2 inbred. The purified proteins differ in their ability to bind F-actin in vitro, suggesting that they are functionally distinct. However, they share similar aminoacyl-tRNA-binding activities. Tandem mass spectrometry revealed that each isoform is composed of the four same gene products, which are modified posttranslationally by methylation and phosphorylation. The chemical differences that account for their different actin-binding activities could not be determined.
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26
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Stuart MK, Chamberlain NR. Monoclonal antibodies to elongation factor-1alpha inhibit in vitro translation in lysates of Sf21 cells. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2003; 52:17-34. [PMID: 12489131 DOI: 10.1002/arch.10061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Elongation factor-1alpha (EF-1alpha) is an enzyme that is essential for protein synthesis. Although EF-1alpha offers an excellent target for the disruption of insect metabolism, agents known to interfere with EF-1alpha activity are toxic to humans. In this article, we describe the development of monoclonal antibodies (MAbs) that can disrupt the activity of insect EF-1alpha without cross-reacting with the human enzyme. MAbs were generated to EF-1alpha from Sf21 cells derived from the fall armyworm, Spodoptera frugiperda, by immunizing mice with EF-1alpha eluted from SDS-PAGE gels. The MAbs reacted with EF-1alpha in eggs and first through fifth instars of the fall armyworm in immunoblots of SDS-PAGE gels, but did not recognize EF-1alpha in human carcinoma cells and normal tissues. MAbs with the ability to recognize EF-1alpha in its native conformation, identified through immunoprecipitation experiments, were added to Sf21 cell lysates to determine whether the antibodies could inhibit incorporation of [(35)S]methionine into newly synthesized in vitro translation products. Of the four EF-1alpha-specific MAbs tested, three significantly inhibited protein synthesis when compared to the negative control antibody (P < 0.001, one-way ANOVA; followed by Dunnett's test, P < 0.05).
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Affiliation(s)
- M K Stuart
- Department of Microbiology/Immunology, Kirksville College of Osteopathic Medicine, Kirksville, Missouri 63501, USA.
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27
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Nandan D, Yi T, Lopez M, Lai C, Reiner NE. Leishmania EF-1alpha activates the Src homology 2 domain containing tyrosine phosphatase SHP-1 leading to macrophage deactivation. J Biol Chem 2002; 277:50190-7. [PMID: 12384497 DOI: 10.1074/jbc.m209210200] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The human leishmaniasis are persistent infections of macrophages caused by protozoa of the genus Leishmania. The chronic nature of these infections is in part related to induction of macrophage deactivation, linked to activation of the Src homology 2 domain containing tyrosine phosphatase-1 (SHP-1) in infected cells. To investigate the mechanism of SHP-1 activation, lysates of Leishmania donovani promastigotes were subjected to SHP-1 affinity chromatography and proteins bound to the matrix were sequenced by mass spectrometry. This resulted in the identification of Leishmania elongation factor-1alpha (EF-1alpha) as a SHP-1-binding protein. Purified Leishmania EF-1alpha, but not host cell EF-1alpha, bound directly to SHP-1 in vitro leading to its activation. Three independent lines of evidence indicated that Leishmania EF-1alpha may be exported from the phagosome thereby enabling targeting of host SHP-1. First, cytosolic fractions prepared from macrophages infected with [(35)S]methionine-labeled organisms contained Leishmania EF-1alpha. Second, confocal, fluorescence microscopy using Leishmania-specific antisera detected Leishmania EF-1alpha in the cytosol of infected cells. Third, co-immunoprecipitation showed that Leishmania EF-1alpha was associated with SHP-1 in vivo in infected cells. Finally, introduction of purified Leishmania EF-1alpha, but not the corresponding host protein into macrophages activated SHP-1 and blocked the induction of inducible nitric-oxide synthase expression in response to interferon-gamma. Thus, Leishmania EF-1alpha is identified as a novel SHP-1-binding and activating protein that recapitulates the deactivated phenotype of infected macrophages.
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Affiliation(s)
- Devki Nandan
- Department of Medicine, Division of Infectious Diseases, The University of British Columbia, Research Institute of the Vancouver Hospital and Health Sciences Center, Vancouver, British Columbia V5Z 3J5, Canada.
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28
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Mueller-Roeber B, Pical C. Inositol phospholipid metabolism in Arabidopsis. Characterized and putative isoforms of inositol phospholipid kinase and phosphoinositide-specific phospholipase C. PLANT PHYSIOLOGY 2002; 130:22-46. [PMID: 12226484 PMCID: PMC166537 DOI: 10.1104/pp.004770] [Citation(s) in RCA: 287] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Phosphoinositides (PIs) constitute a minor fraction of total cellular lipids in all eukaryotic cells. They fulfill many important functions through interaction with a wide range of cellular proteins. Members of distinct inositol lipid kinase families catalyze the synthesis of these phospholipids from phosphatidylinositol. The hydrolysis of PIs involves phosphatases and isoforms of PI-specific phospholipase C. Although our knowledge of the roles played by plant PIs is clearly limited at present, there is no doubt that they are involved in many physiological processes during plant growth and development. In this review, we concentrate on inositol lipid-metabolizing enzymes from the model plant Arabidopsis for which biochemical characterization data are available, namely the inositol lipid kinases and PI-specific phospholipase Cs. The biochemical properties and structure of characterized and genome-predicted isoforms are presented and compared with those of the animal enzymes to show that the plant enzymes have some features clearly unique to this kingdom.
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Affiliation(s)
- Bernd Mueller-Roeber
- Universität Potsdam, Institut für Biochemie und Biologie, Abteilung Molekularbiologie, Karl-Liebknecht-Strasse 25, Haus 20, D-14476 Golm/Potsdam, Germany
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29
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Cheng SH, Willmann MR, Chen HC, Sheen J. Calcium signaling through protein kinases. The Arabidopsis calcium-dependent protein kinase gene family. PLANT PHYSIOLOGY 2002; 129:469-85. [PMID: 12068094 PMCID: PMC1540234 DOI: 10.1104/pp.005645] [Citation(s) in RCA: 503] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In plants, numerous Ca(2+)-stimulated protein kinase activities occur through calcium-dependent protein kinases (CDPKs). These novel calcium sensors are likely to be crucial mediators of responses to diverse endogenous and environmental cues. However, the precise biological function(s) of most CDPKs remains elusive. The Arabidopsis genome is predicted to encode 34 different CDPKs. In this Update, we analyze the Arabidopsis CDPK gene family and review the expression, regulation, and possible functions of plant CDPKs. By combining emerging cellular and genomic technologies with genetic and biochemical approaches, the characterization of Arabidopsis CDPKs provides a valuable opportunity to understand the plant calcium-signaling network.
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Affiliation(s)
- Shu-Hua Cheng
- Department of Genetics, Harvard Medical School, MA 02114, USA
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30
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Chang JS, Seok H, Kwon TK, Min DS, Ahn BH, Lee YH, Suh JW, Kim JW, Iwashita S, Omori A, Ichinose S, Numata O, Seo JK, Oh YS, Suh PG. Interaction of elongation factor-1alpha and pleckstrin homology domain of phospholipase C-gamma 1 with activating its activity. J Biol Chem 2002; 277:19697-702. [PMID: 11886851 DOI: 10.1074/jbc.m111206200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pleckstrin homology (PH) domain is a small motif for membrane targeting in the signaling molecules. Phospholipase C (PLC)-gamma1 has two putative PH domains, an NH(2)-terminal and a split PH domain. Here we report studies on the interaction of the PH domain of PLC-gamma1 with translational elongation factor (EF)-1alpha, which has been shown to be a phosphatidylinositol 4-kinase activator. By pull-down of cell extract with the glutathione S-transferase (GST) fusion proteins with various domains of PLC-gamma1 followed by peptide sequence analysis, we identified EF-1alpha as a binding partner of a split PH domain of PLC-gamma1. Analysis by site-directed mutagenesis of the PH domain revealed that the beta2-sheet of a split PH domain is critical for the interaction with EF-1alpha. Moreover, Dot-blot assay shows that a split PH domain specifically binds to phosphoinositides including phosphatidylinositol 4-phosphate and phosphatidylinositol 4, 5-bisphosphate (PIP(2)). So the PH domain of PLC-gamma1 binds to both EF-1alpha and PIP(2). The binding affinity of EF-1alpha to the GST.PH domain fusion protein increased in the presence of PIP(2), although PIP(2) does not bind to EF-1alpha directly. This suggests that EF-1alpha may control the binding affinity between the PH domain and PIP(2). PLC-gamma1 is substantially activated in the presence of EF-1alpha with a bell-shaped curve in relation to the molar ratio between them, whereas a double point mutant PLC-gamma1 (Y509A/F510A) that lost its binding affinity to EF-1alpha shows basal level activity. Taken together, our data show that EF-1alpha plays a direct role in phosphoinositide metabolism of cellular signaling by regulating PLC-gamma1 activity via a split PH domain.
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Affiliation(s)
- Jong-Soo Chang
- Department of Life Science, College of Natural Science, Daejin University, Kyeonggido 487-711, Korea.
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31
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Reynet C, Kahn CR. Unbalanced expression of the different subunits of elongation factor 1 in diabetic skeletal muscle. Proc Natl Acad Sci U S A 2001; 98:3422-7. [PMID: 11248094 PMCID: PMC30669 DOI: 10.1073/pnas.051630398] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In studies using subtraction cloning to screen for alterations in mRNA expression in skeletal muscle from humans with Type 2 diabetes mellitus and control subjects, one of the most prominent differences was in the mRNA for elongation factor (EF)-1alpha. With Northern blot analysis, EF-1alpha expression was enhanced by 2- to 6-fold in both Types 1 and 2 human diabetics. In contrast, no changes in expression of EF-1beta or -gamma were noted. We observed similar results in animal models of Type 1 diabetes. EF-1alpha expression, but not EF-1beta or -gamma expression, was also enhanced in streptozotocin-induced diabetic rats, and this effect was reversed by insulin treatment. An increased level of EF-1alpha mRNA was also observed in nonobese diabetic mice. This unbalanced regulation of the expression of the different subunits of EF-1 may contribute to alterations not only in protein synthesis but also in other cellular events observed in the diabetic state.
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MESH Headings
- Animals
- Cloning, Molecular
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/pathology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/pathology
- Gene Expression
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Muscle, Skeletal/metabolism
- Peptide Elongation Factor 1/genetics
- RNA, Messenger
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- C Reynet
- Research Division, Joslin Diabetes Center, and Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
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32
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Moore RC, Cyr RJ. Association between elongation factor-1alpha and microtubules in vivo is domain dependent and conditional. CELL MOTILITY AND THE CYTOSKELETON 2000; 45:279-92. [PMID: 10744861 DOI: 10.1002/(sici)1097-0169(200004)45:4<279::aid-cm4>3.0.co;2-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although the precise definition for a microtubule-associated protein (MAP) has been the subject of debate, elongation factor-1alpha (EF-1alpha) fits the most basic criteria for a MAP [Durso and Cyr, 1994a]. It binds, bundles, stabilizes, and promotes the assembly of microtubules in vitro, and localizes to plant microtubule arrays in situ. In this study, the in vitro and in vivo association of EF-1alpha with microtubules was further investigated. Analysis of the in vitro binding data for EF-1alpha and microtubules indicates that EF-1alpha binds cooperatively to the microtubule lattice. In order to investigate the interaction of EF-1alpha with microtubules in vivo, GFP fusions to EF-1alpha or to EF-1alpha truncates were transiently expressed in living plant cells. Using this method, two putative microtubule-binding domains on EF-1alpha were identified: one in the N-terminal domain I and one in the C-terminal domain III. The binding of domain I to microtubules in vivo, like the binding of full-length EF-1alpha, is conditional, and requires incubation in weak, lipophilic organic acids. The binding of domain III to microtubules in vivo, however, is not conditional, and occurs under normal cellular regimes. Furthermore, domain III stabilizes cortical microtubules as determined by their resistance to the anti-microtubule herbicide, oryzalin. Because the accumulation of EF-1alpha onto microtubules is unconditional in the absence of domain I, we hypothesize that domain I negatively regulates the accumulation of EF-1alpha onto microtubules in vivo. This hypothesis is discussed in terms of possible regulatory mechanisms that could affect the accumulation of EF-1alpha onto microtubules within living cells.
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Affiliation(s)
- R C Moore
- Department of Biology and Intercollege Program in Plant Physiology, The Pennsylvania State University, University Park 16802, USA
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33
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Drøbak BK, Dewey RE, Boss WF. Phosphoinositide kinases and the synthesis of polyphosphoinositides in higher plant cells. INTERNATIONAL REVIEW OF CYTOLOGY 1999; 189:95-130. [PMID: 10333579 DOI: 10.1016/s0074-7696(08)61386-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Phosphoinositides are a family of inositol-containing phospholipids which are present in all eukaryotic cells. Although in most cells these lipids, with the exception of phosphatidylinositol, constitute only a very minor proportion of total cellular lipids, they have received immense attention by researchers in the past 15-20 years. This is due to the discovery that these lipids, rather than just having structural functions, play key roles in a wide range of important cellular processes. Much less is known about the plant phosphoinositides than about their mammalian counterparts. However, it has been established that a functional phosphoinositide system exists in plant cells and it is becoming increasingly clear that inositol-containing lipids are likely to play many important roles throughout the life of a plant. It is not our intention to give an exhaustive overview of all aspects of the field, but rather we focus on the phosphoinositide kinases responsible for the synthesis of all phosphorylated forms of phosphatidylinositol. Also, we mention some of the aspects of current phosphoinositide research which, in our opinion, are most likely to provide a suitable starting point for further research into the role of phosphoinositides in plants.
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Affiliation(s)
- B K Drøbak
- Department of Cell Biology, John Innes Centre, Norwich, United Kingdom
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34
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Wang W, Poovaiah BW. Interaction of plant chimeric calcium/calmodulin-dependent protein kinase with a homolog of eukaryotic elongation factor-1alpha. J Biol Chem 1999; 274:12001-8. [PMID: 10207022 DOI: 10.1074/jbc.274.17.12001] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A chimeric Ca2+/calmodulin-dependent protein kinase (CCaMK) was previously cloned and characterized in this laboratory. To investigate the biological functions of CCaMK, the yeast two-hybrid system was used to isolate genes encoding proteins that interact with CCaMK. One of the cDNA clones obtained from the screening (LlEF-1alpha1) has high similarity with the eukaryotic elongation factor-1alpha (EF-1alpha). CCaMK phosphorylated LlEF-1alpha1 in a Ca2+/calmodulin-dependent manner. The phosphorylation site for CCaMK (Thr-257) was identified by site-directed mutagenesis. Interestingly, Thr-257 is located in the putative tRNA-binding region of LlEF-1alpha1. An isoform of Ca2+-dependent protein kinase (CDPK) phosphorylated multiple sites of LlEF-1alpha1 in a Ca2+-dependent but calmodulin-independent manner. Unlike CDPK, CCaMK phosphorylated only one site, and this site is different from CDPK phosphorylation sites. This suggests that the phosphorylation of EF-1alpha by these two kinases may have different functional significance. Although the phosphorylation of LlEF-1alpha1 by CCaMK is Ca2+/calmodulin-dependent, in vitro binding assays revealed that CCaMK binds to LlEF-1alpha1 in a Ca2+-independent manner. This was further substantiated by coimmunoprecipitation of CCaMK and EF-1alpha using the protein extract from lily anthers. Dissociation of CCaMK from EF-1alpha by Ca2+ and phosphorylation of EF-1alpha by CCaMK in a Ca2+/calmodulin-dependent manner suggests that these interactions may play a role in regulating the biological functions of EF-1alpha.
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Affiliation(s)
- W Wang
- Laboratory of Plant Molecular Biology and Physiology, Department of Horticulture, Washington State University, Pullman, Washington 99164-6414, USA
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35
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Xue HW, Pical C, Brearley C, Elge S, Müller-Röber B. A plant 126-kDa phosphatidylinositol 4-kinase with a novel repeat structure. Cloning and functional expression in baculovirus-infected insect cells. J Biol Chem 1999; 274:5738-45. [PMID: 10026194 DOI: 10.1074/jbc.274.9.5738] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol metabolism plays a central role in signaling pathways in animals and is also believed to be of importance in signal transduction in higher plants. We report here the molecular cloning of a cDNA encoding a previously unidentified 126-kDa phosphatidylinositol (PI) 4-kinase (AtPI4Kbeta) from the higher plant Arabidopsis thaliana. The novel protein possesses the conserved domains present in animal and yeast PI 4-kinases, namely a lipid kinase unique domain and a catalytic domain. An additional domain, approximately 300 amino acids long, containing a high percentage (46%) of charged amino acids is specific to this plant enzyme. Recombinant AtPI4Kbeta expressed in baculovirus-infected insect (Spodoptera frugiperda) cells phosphorylated phosphatidylinositol exclusively at the D4 position of the inositol ring. Recombinant protein was maximally activated by 0.6% Triton X-100 but was inhibited by adenosine with an IC50 of approximately 200 microM. Wortmannin at a concentration of 10 microM inhibited AtPI4Kbeta activity by approximately 90%. AtPI4Kbeta transcript levels were similar in all tissues analyzed. Light or treatment with hormones or salts did not change AtPI4Kbeta transcript levels to a great extent, indicating constitutive expression of the AtPI4Kbeta gene.
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Affiliation(s)
- H W Xue
- Max Planck Institute of Molecular Plant Physiology, Karl-Liebknecht-Strabetae 25, Haus 20, D-14476 Golm/Potsdam, Germany
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36
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Abstract
The three-dimensional intracellular network formed by the filamentous polymers comprising the cytoskeletal affects the way cells sense their extracellular environment and respond to stimuli. Because the cytoskeleton is viscoelastic, it provides a continuous mechanical coupling throughout the cell that changes as the cytoskeleton remodels. Such mechanical effects, based on network formation, can influence ion channel activity at the plasma membrane of cells and may conduct mechanical stresses from the cell membrane to internal organelles. As a result, both rapid responses such as changes in intracellular Ca2+ and slower responses such as gene transcription or the onset of apoptosis can be elicited or modulated by mechanical perturbations. In addition to mechanical features, the cytoskeleton also provides a large negatively charged surface on which many signaling molecules including protein and lipid kinases, phospholipases, and GTPases localize in response to activation of specific transmembrane receptors. The resulting spatial localization and concomitant change in enzymatic activity can alter the magnitude and limit the range of intracellular signaling events.
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Affiliation(s)
- P A Janmey
- Experimental Medicine Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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37
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Ransom WD, Lao PC, Gage DA, Boss WF. Phosphoglycerylethanolamine posttranslational modification of plant eukaryotic elongation factor 1alpha. PLANT PHYSIOLOGY 1998; 117:949-960. [PMID: 9662537 PMCID: PMC34949 DOI: 10.1104/pp.117.3.949] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/1998] [Accepted: 04/03/1998] [Indexed: 05/22/2023]
Abstract
Eukaryotic elongation factor 1alpha (eEF-1A) is a multifunctional protein. There are three known posttranslational modifications of eEF-1A that could potentially affect its function. Except for phosphorylation, the other posttranslational modifications have not been demonstrated in plants. Using matrix-assisted laser desorption/ionization-mass spectrometry and peptide mass mapping, we show that carrot (Daucus carota L.) eEF-1A contains a phosphoglycerylethanolamine (PGE) posttranslational modification. eEF-1A was the only protein labeled with [14C]ethanolamine in carrot cells and was the predominant ethanolamine-labeled protein in Arabidopsis seedlings and tobacco (Nicotiana tabacum L.) cell cultures. In vivo-labeling studies using [3H]glycerol, [32P]Pi, [14C]myristic acid, and [14C]linoleic acid indicated that the entire phospholipid phosphatidylethanolamine is covalently attached to the protein. The PGE lipid modification did not affect the partitioning of eEF-1A in Triton X-114 or its actin-binding activity in in vitro assays. Our in vitro data indicate that this newly characterized posttranslational modification alone does not affect the function of eEF-1A. Therefore, the PGE lipid modification may work in combination with other posttranslational modifications to affect the distribution and the function of eEF-1A within the cell.
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Affiliation(s)
- W D Ransom
- Botany Department, North Carolina State University, Raleigh, North Carolina 27695-7612, USA.
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38
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Gallie DR, Le H, Caldwell C, Browning KS. Analysis of translation elongation factors from wheat during development and following heat shock. Biochem Biophys Res Commun 1998; 245:295-300. [PMID: 9571144 DOI: 10.1006/bbrc.1998.8427] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Translational activity in plants undergoes rapid changes during developmental stages such as seed formation and germination, and during abiotic stresses such as heat shock, hypoxia and wounding. We examined the protein levels and isoelectric state of two components of the translation machinery, elongation factor (EF) 1 alpha and 2, to determine their roles in the regulation of translation. We found that the apparent protein levels of EF1 alpha increase relative to the EF2 levels which decline slightly during the development of the wheat seed. During germination, high levels of these factors are present in seedling tissues known to be actively engaged in translation; however, no differences in isoelectric state were observed during germination. As an example of abiotic stress, heat shock had little impact on the apparent levels of EF1 alpha or EF2 present in wheat leaves, nor were changes in the number or levels of isoforms observed.
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Affiliation(s)
- D R Gallie
- Department of Biochemistry, University of California, Riverside 92521-0129, USA
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39
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Morelli JK, Zhou W, Yu J, Lu C, Vayda ME. Actin depolymerization affects stress-induced translational activity of potato tuber tissue. PLANT PHYSIOLOGY 1998; 116:1227-37. [PMID: 9536039 PMCID: PMC35029 DOI: 10.1104/pp.116.4.1227] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/1997] [Accepted: 12/07/1997] [Indexed: 05/21/2023]
Abstract
Changes in polymerized actin during stress conditions were correlated with potato (Solanum tuberosum L.) tuber protein synthesis. Fluorescence microscopy and immunoblot analyses indicated that filamentous actin was nearly undetectable in mature, quiescent aerobic tubers. Mechanical wounding of postharvest tubers resulted in a localized increase of polymerized actin, and microfilament bundles were visible in cells of the wounded periderm within 12 h after wounding. During this same period translational activity increased 8-fold. By contrast, low-oxygen stress caused rapid reduction of polymerized actin coincident with acute inhibition of protein synthesis. Treatment of aerobic tubers with cytochalasin D, an agent that disrupts actin filaments, reduced wound-induced protein synthesis in vivo. This effect was not observed when colchicine, an agent that depolymerizes microtubules, was used. Neither of these drugs had a significant effect in vitro on run-off translation of isolated polysomes. However, cytochalasin D did reduce translational competence in vitro of a crude cellular fraction containing both polysomes and cytoskeletal elements. These results demonstrate the dependence of wound-induced protein synthesis on the integrity of microfilaments and suggest that the dynamics of the actin cytoskeleton may affect translational activity during stress conditions.
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Affiliation(s)
- JK Morelli
- Department of Biochemistry, Microbiology and Molecular Biology, University of Maine, Orono, Maine 04469-5735, USA
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40
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Munnik T, Irvine RF, Musgrave A. Phospholipid signalling in plants. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1389:222-72. [PMID: 9512651 DOI: 10.1016/s0005-2760(97)00158-6] [Citation(s) in RCA: 257] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- T Munnik
- Institute for Molecular Cell Biology, BioCentrum Amsterdam, University of Amsterdam, The Netherlands.
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41
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Duttaroy A, Bourbeau D, Wang XL, Wang E. Apoptosis rate can be accelerated or decelerated by overexpression or reduction of the level of elongation factor-1 alpha. Exp Cell Res 1998; 238:168-76. [PMID: 9457069 DOI: 10.1006/excr.1997.3819] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Peptide chain elongation factor-1 alpha (EF-1 alpha) is required for the binding of aminoacyl-tRNAs to acceptor sites of ribosomes during protein synthesis. More recently, EF-1 alpha has been shown to be involved in cytoskeletal organization. The elongation factor functions in actin bundling and microtubule severing. Moreover, it can activate the phosphatidylinositol-4 kinase whose substrates are involved in regulation of actin polymerization. The expression level of EF-1 alpha is regulated in many situations such as growth arrest, transformation, and aging. Because of this regulation of EF-1 alpha in various states of cell life, and its key position in protein synthesis as well as cytoskeletal organization, we chose to investigate the effect of its expression levels on apoptosis. Apoptosis is a complex event regulated through numerous activators and inhibitors. In some situations, protein synthesis is required for apoptosis to be triggered. Investigation of the effect of altered levels of elongation factor-1 alpha on apoptosis is of particular interest since it may affect both protein synthesis and cytoskeletal organization. For example, reduction of EF-1 alpha leads to a reduced protein synthesis rate, which might reduce the presence of those "killer factors" triggering apoptosis. EF-1 alpha involvement in cytoskeletal organization is another example, since cytoskeletal organization undergoes dramatic changes during apoptosis. Thus, this study has been planned to ascertain whether hypo- and hyperexpression of EF-1 alpha protein, achieved by constructing expression vectors with the EF-1 alpha cDNA in its antisense or sense orientation under the control of a cytomegalovirus promoter, can produce stable transfectants with either heightened or reduced responsiveness to apoptosis stimuli. Our results show the following: (1) induction of apoptosis by serum deprivation shows that antisense EF-1 alpha provides cells significant protection from apoptotic cell death and (2) EF-1 alpha overexpression causes a faster rate of cell death. These findings suggest that when EF-1 alpha protein is abundant the cells are proapoptosis, and vice versa in low abundance the cells are in the mode of antiapoptosis. Therefore, changes in levels of EF-1 alpha may be one of the global pivotal regulators modulating the rate of apoptosis.
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Affiliation(s)
- A Duttaroy
- Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec, Canada
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42
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Mikulík K. The role of GTP-binding proteins in mechanochemical movements of microorganisms and their potential to form filamentous structures. Folia Microbiol (Praha) 1998; 43:339-52. [PMID: 9821287 DOI: 10.1007/bf02818572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Prokaryotic cells contain proteins which form extended chains or multimers that oscillate between monomers and oligomers of varying length. Hydrolysis of nucleoside triphosphates combined with site-specific disposition of substrates and products to monomers and multimers is the driving force of dynamic instability of these molecules. Polymeric structures are connected in some manner to a variety of signaling systems that adhere to the polymeric matrix, including the GTP-binding protein(s), protein kinases and phosphatases, and other proteins or systems that communicate between the cytoplasmic membrane and the cytosol. Flexible organization allowing regulated dynamic movement is one of the key elements in all living cells. In eukaryotic cells actin and tubulin are the two main components of dynamically controlled spatial system. These proteins are noteworthy for their ability to polymerize, reversibly, into filaments or microtubules in association with hydrolysis of ATP or GTP, respectively. As such, they regulate most of the mechanics of cell movement including cell division, cell differentiation, phagocytosis and other dynamic phenomena. Recent evidence revealed that microbial cells create functional domains at specific sites of the cells and can form cytoplasmic tubules and fibers.
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Affiliation(s)
- K Mikulík
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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43
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Ladeira de Campos CB, Lopes UG. Leishmania braziliensis, molecular characterization of an elongation factor 1alpha gene. Gene 1997; 198:281-8. [PMID: 9370293 DOI: 10.1016/s0378-1119(97)00329-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The elongation factor EF-1alpha is one of the most studied components of the translation machinery owing to its abundance and possible role in other cellular functions. EF-1alpha mediates the correct coupling of the aminoacyl-tRNA on the A site of the ribosome in a GTP-dependent reaction. We have previously described an EF-1alpha DNA sequence in Leishmania amazonensis, pLEF11 (accession No. M92653), using PCR. In this paper we describe the DNA sequence and genomic organization of L. braziliensis EF-1alpha gene. Southern blot analysis revealed that EF-1alpha is organized as a 2 kb tandem repeat. The pLEF11 probe recognized a 1.8 kb mRNA from promastigotes in Northern blots. A clone containing the first copy and a half of the EF-1alpha tandem repeat was isolated by screening a L. braziliensis genomic library. Southern blot analysis showed that the isolated clone (lambda2.2) presented the same hybridization profile as that of a genomic blot. The partial sequencing of clone lambda2.2 spans 2959 nucleotides in length, which has two open reading frames separated by a putative non-coding region. The nucleotide and the predicted peptide sequence of the first coding region presented approximately 80% identity with other eukaryotic EF-1alpha genes. The sequence also displayed the four consensus motifs corresponding to the GTP-binding site (G1, G2, G3 and G4). Computer analysis of the sequence of both coding regions revealed three divergent nucleotides, which generated two changes at the amino acid level. One was found to be located in the G2 domain. The non-coding region of the EF-1alpha gene sequence showed potential regulatory elements such as polypyrimidine tracks, chi-homologous sequences and stem-loop forming sequences.
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Affiliation(s)
- C B Ladeira de Campos
- Instituto de Biofisica Carlos Chagas Filho, UFRJ, CCS, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, Brazil
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Cavallius J, Popkie AP, Merrick WC. Site-directed mutants of post-translationally modified sites of yeast eEF1A using a shuttle vector containing a chromogenic switch. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1350:345-58. [PMID: 9061031 DOI: 10.1016/s0167-4781(96)00181-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Eukaryotic elongation factor 1A (eEF1A, formerly eEF-1 alpha) carries aminoacyl-tRNAs into the A-site of the ribosome in a GTP-dependent manner. In order to probe the structure/function relationships of eEF1A, we have generated site-directed mutants using a modification of a highly versatile yeast shuttle vector, which consists of the insertion of a 66 base long synthetic DNA fragment in the vector's polylinker. Via oligonucleotide-directed mutagenesis, the modification permits the identification of mutant clones based on a chromogenic screen of beta-galactosidase activity. Mutagenesis reactions are performed with two or more oligonucleotides, one introducing the chromogenic shift, and the other(s) introducing the mutation(s) of interest in eEF1A. Several rounds of chromogenic shifts and additional mutations can be performed in succession on the same vector. To address the possible function of the methylated lysines in yeast eEF1A, we have changed the post-translationally modified lysines (residue 30, 79, 316 and 390) to arginines using the above methodology. Yeast with eEF1A mutants that substitute arginine in all four sites do not show any phenotypic change. There is also an apparent equivalency of wild-type and mutant yeast eEF1A in in vitro assays. It is concluded that the post-translational modifications of eEF1A are not of major importance for eEF1A's role in translation.
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Affiliation(s)
- J Cavallius
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4935, USA.
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45
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Abstract
Protein synthesis in both eukaryotic and prokaryotic cells is a complex process requiring a large number of macromolecules: initiation factors, elongation factors, termination factors, ribosomes, mRNA, amino-acylsynthetases and tRNAs. This review focuses on our current knowledge of protein synthesis in higher plants.
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Affiliation(s)
- K S Browning
- Department of Chemistry and Biochemistry, University of Texas at Austin 78712, USA
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46
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Ridgley EL, Xiong ZH, Kaur KJ, Ruben L. Genomic organization and expression of elongation factor-1 alpha genes in Trypanosoma brucei. Mol Biochem Parasitol 1996; 79:119-23. [PMID: 8844680 DOI: 10.1016/0166-6851(96)02639-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- E L Ridgley
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
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47
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Affiliation(s)
- M H Cho
- Botany Department, North Carolina State University, Raleigh 27695-7612, USA
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