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Davarinejad H, Arvanitis-Vigneault A, Nygard D, Lavallée-Adam M, Couture JF. Modus operandi: Chromatin recognition by α-helical histone readers. Structure 2024; 32:8-17. [PMID: 37922903 DOI: 10.1016/j.str.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023]
Abstract
Histone reader domains provide a mechanism for sensing states of coordinated nuclear processes marked by histone proteins' post-translational modifications (PTMs). Among a growing number of discovered histone readers, the 14-3-3s, ankyrin repeat domains (ARDs), tetratricopeptide repeats (TPRs), bromodomains (BRDs), and HEAT domains are a group of domains using various mechanisms to recognize unmodified or modified histones, yet they all are composed of an α-helical fold. In this review, we compare how these readers fold to create protein domains that are very diverse in their tertiary structures, giving rise to intriguing peptide binding mechanisms resulting in vastly different footprints of their targets.
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Affiliation(s)
- Hossein Davarinejad
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Alexis Arvanitis-Vigneault
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Dallas Nygard
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Mathieu Lavallée-Adam
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada
| | - Jean-François Couture
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON K1H 8M5, Canada.
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2
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Li M, Quan C, Chen S, Wang HY. The 14-3-3 protein is an essential component of cyclic AMP signaling for regulation of chemotaxis and development in Dictyostelium. Cell Signal 2020; 75:109739. [PMID: 32818671 DOI: 10.1016/j.cellsig.2020.109739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 10/23/2022]
Abstract
The evolutionarily-conserved 14-3-3 proteins regulate many cellular processes through binding to various phosphorylated targets in eukaryotes. It first appears in Dictyostelium, however its role in this organism is poorly understood. Here we show that down-regulation of the 14-3-3 impairs chemotaxis and causes multiple-tip formation in Dictyostelium. Mechanistically, the 14-3-3 is a critical component of cyclic AMP (cAMP) signaling and binds to nearly a hundred of proteins in Dictyostelium, including a number of evolutionarily-conserved proteins. 14-3-3 - interaction with its targets is up-regulated in response to developmental cues/regulators including starvation, osmotic stress and cAMP. cAMP stimulates 14-3-3 - binding to phospho-Ser431 on a guanine nucleotide exchange factor Gef-Q. Interestingly, overexpression of Gef-QSer431Ala mutant but not wild-type Gef-Q protein causes a multiple-tip phenotype in Dictyostelium, which partially resembles phenotypes of the 14-3-3 - deficient mutant. Collectively, these data demonstrate that the 14-3-3 plays an important role in Dictyostelium and may help to deepen our understanding of the evolution of 14-3-3 - interactomes in eukaryotes.
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Affiliation(s)
- Min Li
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Chao Quan
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China
| | - Shuai Chen
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China; Nanjing Biomedical Research Institute, Nanjing University, Nanjing 210061, China.
| | - Hong Yu Wang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Pukou District, Nanjing 210061, China.
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3
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Pennington KL, Chan TY, Torres MP, Andersen JL. The dynamic and stress-adaptive signaling hub of 14-3-3: emerging mechanisms of regulation and context-dependent protein-protein interactions. Oncogene 2018; 37:5587-5604. [PMID: 29915393 PMCID: PMC6193947 DOI: 10.1038/s41388-018-0348-3] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/07/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
14-3-3 proteins are a family of structurally similar phospho-binding proteins that regulate essentially every major cellular function. Decades of research on 14-3-3s have revealed a remarkable network of interacting proteins that demonstrate how 14-3-3s integrate and control multiple signaling pathways. In particular, these interactions place 14-3-3 at the center of the signaling hub that governs critical processes in cancer, including apoptosis, cell cycle progression, autophagy, glucose metabolism, and cell motility. Historically, the majority of 14-3-3 interactions have been identified and studied under nutrient-replete cell culture conditions, which has revealed important nutrient driven interactions. However, this underestimates the reach of 14-3-3s. Indeed, the loss of nutrients, growth factors, or changes in other environmental conditions (e.g., genotoxic stress) will not only lead to the loss of homeostatic 14-3-3 interactions, but also trigger new interactions, many of which are likely stress adaptive. This dynamic nature of the 14-3-3 interactome is beginning to come into focus as advancements in mass spectrometry are helping to probe deeper and identify context-dependent 14-3-3 interactions-providing a window into adaptive phosphorylation-driven cellular mechanisms that orchestrate the tumor cell's response to a variety of environmental conditions including hypoxia and chemotherapy. In this review, we discuss emerging 14-3-3 regulatory mechanisms with a focus on post-translational regulation of 14-3-3 and dynamic protein-protein interactions that illustrate 14-3-3's role as a stress-adaptive signaling hub in cancer.
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Affiliation(s)
- K L Pennington
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - T Y Chan
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - M P Torres
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - J L Andersen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
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4
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Kumar R. An account of fungal 14-3-3 proteins. Eur J Cell Biol 2017; 96:206-217. [PMID: 28258766 DOI: 10.1016/j.ejcb.2017.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 01/09/2023] Open
Abstract
14-3-3s are a group of relatively low molecular weight, acidic, dimeric, protein(s) conserved from single-celled yeast to multicellular vertebrates including humans. Despite lacking catalytic activity, these proteins have been shown to be involved in multiple cellular processes. Apart from their role in normal cellular physiology, recently these proteins have been implicated in various medical consequences. In this present review, fungal 14-3-3 protein localization, interactions, transcription, regulation, their role in the diverse cellular process including DNA duplication, cell cycle, protein trafficking or secretion, apoptosis, autophagy, cell viability under stress, gene expression, spindle positioning, role in carbon metabolism have been discussed. In the end, I also highlighted various roles of yeasts 14-3-3 proteins in tabular form. Thus this review with primary emphasis on yeast will help in appreciating the significance of 14-3-3 proteins in cell physiology.
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Affiliation(s)
- Ravinder Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, Maharashtra, India.
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5
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de Boer AH, van Kleeff PJM, Gao J. Plant 14-3-3 proteins as spiders in a web of phosphorylation. PROTOPLASMA 2013; 250:425-40. [PMID: 22926776 DOI: 10.1007/s00709-012-0437-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 07/18/2012] [Indexed: 05/17/2023]
Abstract
Protein phosphorylation is essential for many aspects of plant growth and development. To fully modulate the activity of specific proteins after phosphorylation, interaction with members of the 14-3-3 family is necessary. 14-3-3 Proteins are important for many processes because they "assist" a wide range of target proteins with divergent functions. In this review, we will describe how plant 14-3-3 proteins are as spiders in a web of phosphorylation: they act as sensors for phospho-motifs, they themselves are phosphorylated with unknown consequences and they have kinases as target, where some of these phosphorylate 14-3-3 binding motifs in other proteins. Two specific classes of 14-3-3 targets, protein kinases and transcription factors of the bZIP and basic helix-loop-helix-like families, with important and diverse functions in the plant as a whole will be discussed. An important question to be addressed in the near future is how the interaction with 14-3-3 proteins has diverged, both structurally and functionally, between different members of the same protein family, like the kinases and transcription factors.
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Affiliation(s)
- Albertus H de Boer
- Faculty of Earth & Life Sciences, Department of Structural Biology, Vrije Universiteit, De Boelelaan 1085, 1081 HV, Amsterdam, Netherlands.
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6
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Sugden C, Ross S, Bloomfield G, Ivens A, Skelton J, Mueller-Taubenberger A, Williams JG. Two novel Src homology 2 domain proteins interact to regulate dictyostelium gene expression during growth and early development. J Biol Chem 2010; 285:22927-35. [PMID: 20457612 PMCID: PMC2906285 DOI: 10.1074/jbc.m110.139733] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Indexed: 01/01/2023] Open
Abstract
There are 13 Dictyostelium Src homology 2 (SH2) domain proteins, almost 10-fold fewer than in mammals, and only three are functionally unassigned. One of these, LrrB, contains a novel combination of protein interaction domains: an SH2 domain and a leucine-rich repeat domain. Growth and early development appear normal in the mutant, but expression profiling reveals that three genes active at these stages are greatly underexpressed: the ttdA metallohydrolase, the abcG10 small molecule transporter, and the cinB esterase. In contrast, the multigene family encoding the lectin discoidin 1 is overexpressed in the disruptant strain. LrrB binds to 14-3-3 protein, and the level of binding is highest during growth and decreases during early development. Comparative tandem affinity purification tagging shows that LrrB also interacts, via its SH2 domain and in a tyrosine phosphorylation-dependent manner, with two novel proteins: CldA and CldB. Both of these proteins contain a Clu domain, a >200-amino acid sequence present within highly conserved eukaryotic proteins required for correct mitochondrial dispersal. A functional interaction of LrrB with CldA is supported by the fact that a cldA disruptant mutant also underexpresses ttdA, abcG10, and cinB. Significantly, CldA is itself one of the three functionally unassigned SH2 domain proteins. Thus, just as in metazoa, but on a vastly reduced numerical scale, an interacting network of SH2 domain proteins regulates specific Dictyostelium gene expression.
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Affiliation(s)
- Christopher Sugden
- From the
School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, United Kingdom
| | - Susan Ross
- From the
School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, United Kingdom
| | - Gareth Bloomfield
- the
Wellcome Trust Sanger Institute, Hinxton CB10 1SA, United Kingdom
| | - Alasdair Ivens
- the
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom, and
| | - Jason Skelton
- the
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom, and
| | - Annette Mueller-Taubenberger
- the
Institute for Cell Biology and Center for Integrated Protein Science, Munich, Ludwig Maximilians University, Schillerstrasse 42, D-80336 Munich, Germany
| | - Jeffrey G. Williams
- From the
School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, United Kingdom
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7
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Abstract
14-3-3 proteins form a family of highly conserved proteins which are present in all eukaryotic organisms investigated, often in multiple isoforms, up to 13 in some plants. They interact with more than 200 different, mostly phosphorylated proteins. The molecular consequences of 14-3-3 binding are diverse: this binding may result in stabilization of the active or inactive phosphorylated form of the protein, to a conformational alteration leading to activation or inhibition, to a different subcellular localization, to the interaction with other proteins or to shielding of binding sites. The binding partners, and hence the 14-3-3 proteins, are involved in almost every cellular process and 14-3-3 proteins have been linked to several diseases, such as cancer, Alzheimer's disease, the neurological Miller-Dieker and spinocerebellar ataxia type 1 diseases and bovine spongiform encephalopathy (BSE). The yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe both have two genes encoding 14-3-3 proteins, BMH1 and BMH2 and rad24 and rad25, respectively. In these yeasts, 14-3-3 proteins are essential in most laboratory strains. As in higher eukaryotes, yeast 14-3-3 proteins bind to numerous proteins involved in a variety of cellular processes. Recent genome-wide studies on yeast strains with impaired 14-3-3 function support the participation of 14-3-3 proteins in numerous yeast cellular processes. Given the high evolutionary conservation of the 14-3-3 proteins, the experimental accessibility and relative simplicity of yeasts make them excellent model organisms for elucidating the function of the 14-3-3 protein family.
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Affiliation(s)
- G Paul H van Heusden
- Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands.
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8
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Bruckmann A, Steensma H, Teixeira de Mattos M, van Heusden G. Regulation of transcription by Saccharomyces cerevisiae 14-3-3 proteins. Biochem J 2005; 382:867-75. [PMID: 15142031 PMCID: PMC1133962 DOI: 10.1042/bj20031885] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2003] [Revised: 04/28/2004] [Accepted: 05/14/2004] [Indexed: 12/22/2022]
Abstract
14-3-3 proteins form a family of highly conserved eukaryotic proteins involved in a wide variety of cellular processes, including signalling, apoptosis, cell-cycle control and transcriptional regulation. More than 150 binding partners have been found for these proteins. The yeast Saccharomyces cerevisiae has two genes encoding 14-3-3 proteins, BMH1 and BMH2. A bmh1 bmh2 double mutant is unviable in most laboratory strains. Previously, we constructed a temperature-sensitive bmh2 mutant and showed that mutations in RTG3 and SIN4, both encoding transcriptional regulators, can suppress the temperature-sensitive phenotype of this mutant, suggesting an inhibitory role of the 14-3-3 proteins in Rtg3-dependent transcription [van Heusden and Steensma (2001) Yeast 18, 1479-1491]. In the present paper, we report a genome-wide transcription analysis of a temperature-sensitive bmh2 mutant. Steady-state mRNA levels of 60 open reading frames were increased more than 2.0-fold in the bmh2 mutant, whereas those of 78 open reading frames were decreased more than 2.0-fold. In agreement with our genetic experiments, six genes known to be regulated by Rtg3 showed elevated mRNA levels in the mutant. In addition, several genes with other cellular functions, including those involved in gluconeogenesis, ergosterol biosynthesis and stress response, had altered mRNA levels in the mutant. Our data show that the yeast 14-3-3 proteins negatively regulate Rtg3-dependent transcription, stimulate the transcription of genes involved in ergosterol metabolism and in stress response and are involved in transcription regulation of multiple other genes.
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Affiliation(s)
- Astrid Bruckmann
- *Section Yeast Genetics, Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
| | - H. Yde Steensma
- *Section Yeast Genetics, Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
- †Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - M. Joost Teixeira de Mattos
- ‡Department of Microbiology, Swammerdam Institute of Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - G. Paul H. van Heusden
- *Section Yeast Genetics, Institute of Biology, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
- To whom correspondence should be addressed (email )
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9
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Aubry L, Lee S, Ravanel K, Firtel RA. The novel ankyrin-repeat containing kinase ARCK-1 acts as a suppressor of the Spalten signaling pathway during Dictyostelium development. Dev Biol 2003; 263:308-22. [PMID: 14597204 DOI: 10.1016/j.ydbio.2003.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Spalten (Spn), a member of the PP2C family of Ser/Thr protein phosphatases, is required for Dictyostelium cell-type differentiation and morphogenesis. We have identified a new protein kinase, ARCK-1, through a second site suppressor screen for mutants that allow spn null cells to proceed further through development. ARCK-1 has a C-terminal kinase domain most closely related to Ser/Thr protein kinases and an N-terminal putative regulatory domain with ankyrin repeats, a 14-3-3 binding domain, and a C1 domain, which is required for binding to RasBGTP in a two-hybrid assay. Disruption of the gene encoding ARCK-1 results in weak, late developmental defects. However, overexpression of ARCK-1 phenocopies the spn null phenotype, consistent with Spn and ARCK-1 being on the same developmental pathway. Our previous analyses of Spn and the present analysis of ARCK-1 suggest a model in which Spn and ARCK-1 differentially control the phosphorylation state of a protein that regulates cell-type differentiation. Dephosphorylation of the substrate by Spn is required for cell-type differentiation. Control of ARCK-1 and Spn activities by upstream signals is proposed to be part of the developmental regulatory program mediating cell-fate decisions in Dictyostelium.
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Affiliation(s)
- Laurence Aubry
- Laboratoire de Biochimie et Biophysique des Systèmes Intégrés (UMR 5092 CNRS-CEA-UJF), DRDC/BBSI, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
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10
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van Hemert MJ, Deelder AM, Molenaar C, Steensma HY, van Heusden GPH. Self-association of the spindle pole body-related intermediate filament protein Fin1p and its phosphorylation-dependent interaction with 14-3-3 proteins in yeast. J Biol Chem 2003; 278:15049-55. [PMID: 12551942 DOI: 10.1074/jbc.m212495200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Fin1 protein of the yeast Saccharomyces cerevisiae forms filaments between the spindle pole bodies of dividing cells. In the two-hybrid system it binds to 14-3-3 proteins, which are highly conserved proteins involved in many cellular processes and which are capable of binding to more than 120 different proteins. Here, we describe the interaction of the Fin1 protein with the 14-3-3 proteins Bmh1p and Bmh2p in more detail. Purified Fin1p interacts with recombinant yeast 14-3-3 proteins. This interaction is strongly reduced after dephosphorylation of Fin1p. Surface plasmon resonance analysis showed that Fin1p has a higher affinity for Bmh2p than for Bmh1p (K(D) 289 versus 585 nm). Sequences in both the central and C-terminal part of Fin1p are required for the interaction with Bmh2p in the two-hybrid system. In yeast strains lacking 14-3-3 proteins Fin1 filament formation was observed, indicating that the 14-3-3 proteins are not required for this process. Fin1 also interacts with itself in the two-hybrid system. For this interaction sequences at the C terminus, containing one of two putative coiled-coil regions, are sufficient. Fin1p-Fin1p interactions were demonstrated in vivo by fluorescent resonance energy transfer between cyan fluorescent protein-labeled Fin1p and yellow fluorescent protein-labeled Fin1p.
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Affiliation(s)
- Martijn J van Hemert
- Section Yeast Genetics, Institute of Molecular Plant Sciences, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
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11
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van Heusden GP, Steensma HY. 14-3-3 Proteins are essential for regulation of RTG3-dependent transcription in Saccharomyces cerevisiae. Yeast 2001; 18:1479-91. [PMID: 11748725 DOI: 10.1002/yea.765] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
14-3-3 proteins comprise a family of highly conserved proteins that bind more than 60 different, mostly phosphorylated, proteins. The yeast Saccharomyces cerevisiae has two genes, BMH1 and BMH2, encoding 14-3-3 proteins. Disruption of both genes together is lethal. In this study we constructed a mutant with a single, temperature-sensitive bmh allele. Recessive mutations in SIN4 and RTG3 can suppress the temperature-sensitive phenotype of this mutant. These genes encode a global transcriptional regulator and a basic helix-loop-helix transcription factor, respectively. The yeast 14-3-3 proteins were shown to bind to the Rtg3 protein. Overexpression of RTG3 is lethal even in wild-type cells. These genetic and biochemical data are consistent with a model in which the 14-3-3 proteins are required to keep the Rtg3 protein in an inactive state, which is (one of) the essential function(s) of the 14-3-3 proteins.
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Affiliation(s)
- G P van Heusden
- Section of Yeast Genetics, Institute of Molecular Plant Sciences, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands.
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12
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Al-Khedery B, Barnwell JW, Galinski MR. Stage-specific expression of 14-3-3 in asexual blood-stage Plasmodium. Mol Biochem Parasitol 1999; 102:117-30. [PMID: 10477181 DOI: 10.1016/s0166-6851(99)00090-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper reports the identification of 14-3-3 in Plasmodium. 14-3-3 is an evolutionarily conserved protein that is most noted as a mediator in signal transduction events and cell cycle regulation. The complete cDNA (approximately 2.6 kb) and gDNA (approximately 3.4 kb) of a Plasmodium knowlesi 14-3-3 (Pk14-3-3) is reported. The gene has three introns; two near the beginning and one close to the end of the coding sequence. Also reported, is the gDNA of the Plasmodium falciparum homologue (Pf14-3-3). Unlike in many other organisms, where multiple gene copies and different functional isoforms exist, Plasmodium 14-3-3 is encoded as a single-copy gene. Northern blot analyses show that the Pk14-3-3 transcript in asexual blood stages begins to be expressed in the ring-stage, predominates in young trophozoites, and thereafter declines. An antiserum produced against recombinant Pk14-3-3 reacts via immunoblot and immunoprecipitation with the approximately 30 kDa and the approximately 32 kDa Pk14-3-3 and Pf14-3-3 proteins, respectively. Protein expression in P. knowlesi closely mimics the pattern of the transcript.
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Affiliation(s)
- B Al-Khedery
- Department of Medical and Molecular Parasitology, New York University School of Medicine, NY 10010, USA
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