1
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Wang PP, Jiang X, Zhu L, Zhou D, Hong M, He L, Chen L, Yao S, Zhao Y, Chen G, Wang C, Cui L, Cao Y, Zhu X. A G-Protein-Coupled Receptor Modulates Gametogenesis via PKG-Mediated Signaling Cascade in Plasmodium berghei. Microbiol Spectr 2022; 10:e0015022. [PMID: 35404079 PMCID: PMC9045217 DOI: 10.1128/spectrum.00150-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/20/2022] [Indexed: 12/13/2022] Open
Abstract
Gametogenesis is essential for malaria parasite transmission, but the molecular mechanism of this process remains to be refined. Here, we identified a G-protein-coupled receptor 180 (GPR180) that plays a critical role in signal transduction during gametogenesis in Plasmodium. The P. berghei GPR180 was predominantly expressed in gametocytes and ookinetes and associated with the plasma membrane in female gametes and ookinetes. Knockout of pbgpr180 (Δpbgpr180) had no noticeable effect on blood-stage development but impaired gamete formation and reduced transmission of the parasites to mosquitoes. Transcriptome analysis revealed that a large proportion of the dysregulated genes in the Δpbgpr180 gametocytes had assigned functions in cyclic nucleotide signal transduction. In the Δpbgpr180 gametocytes, the intracellular cGMP level was significantly reduced, and the cytosolic Ca2+ mobilization showed a delay and a reduction in the magnitude during gametocyte activation. These results suggest that PbGPR180 functions upstream of the cGMP-protein kinase G-Ca2+ signaling pathway. In line with this functional prediction, the PbGPR180 protein was found to interact with several transmembrane transporter proteins and the small GTPase Rab6 in activated gametocytes. Allele replacement of pbgpr180 with the P. vivax ortholog pvgpr180 showed equal competence of the transgenic parasite in sexual development, suggesting functional conservation of this gene in Plasmodium spp. Furthermore, an anti-PbGPR180 monoclonal antibody and the anti-PvGPR180 serum possessed robust transmission-blocking activities. These results indicate that GPR180 is involved in signal transduction during gametogenesis in malaria parasites and is a promising target for blocking parasite transmission. IMPORTANCE Environmental changes from humans to mosquitoes activate gametogenesis of the malaria parasite, an obligative process for parasite transmission, but how the signals are relayed remains poorly understood. Here, we show the identification of a Plasmodium G-protein-coupled receptor, GPR180, and the characterization of its function in gametogenesis. In P. berghei, GPR180 is dispensable for asexual development and gametocytogenesis, but its deletion impairs gametogenesis and reduces transmission to mosquitoes. GPR180 appears to function upstream of the cGMP-protein kinase G-Ca2+ signaling pathway and is required for the maximum activity of this pathway. Genetic complementation shows that the GPR180 ortholog from the human malaria parasite P. vivax was fully functional in P. berghei, indicating functional conservation of GPR180 in Plasmodium spp. With predominant expression and membrane association of GPR180 in sexual stages, GPR180 is a promising target for blocking transmission, and antibodies against GPR180 possess robust transmission-blocking activities.
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Affiliation(s)
- Peng-peng Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xuefeng Jiang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Liying Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Dan Zhou
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Mingyang Hong
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lu He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lumeng Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Shijie Yao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Guang Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Basic Medical Sciences, Taizhou University Hospital, Taizhou University, Taizhou, China
| | - Chengqi Wang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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2
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Parreira KS, Scarpelli P, Rezende Lima W, Garcia RS. Contribution of Transcriptome to Elucidate the Biology of Plasmodium spp. Curr Top Med Chem 2022; 22:169-187. [PMID: 35021974 DOI: 10.2174/1568026622666220111140803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/22/2021] [Accepted: 12/26/2021] [Indexed: 11/22/2022]
Abstract
In the present review, we discuss some of the new technologies that have been applied to elucidate how Plasmodium spp escape from the immune system and subvert the host physiology to orchestrate the regulation of its biological pathways. Our manuscript describes how techniques such as microarray approaches, RNA-Seq and single-cell RNA sequencing have contributed to the discovery of transcripts and changed the concept of gene expression regulation in closely related malaria parasite species. Moreover, the text highlights the contributions of high-throughput RNA sequencing for the current knowledge of malaria parasite biology, physiology, vaccine target and the revelation of new players in parasite signaling.
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Affiliation(s)
| | - Pedro Scarpelli
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo - USP, São Paulo, Brazil
| | - Wânia Rezende Lima
- Departamento de Medicina, Instituto de Biotecnologia-Universidade Federal de Catalão
| | - R S Garcia
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo - USP, São Paulo, Brazil
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3
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Huang J, Byun JA, VanSchouwen B, Henning P, Herberg FW, Kim C, Melacini G. Dynamical Basis of Allosteric Activation for the Plasmodium falciparum Protein Kinase G. J Phys Chem B 2021; 125:6532-6542. [PMID: 34115498 DOI: 10.1021/acs.jpcb.1c03622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is required for the progression of the Plasmodium's life cycle and is therefore a promising malaria drug target. PfPKG includes four cGMP-binding domains (CBD-A to CBD-D). CBD-D plays a crucial role in PfPKG regulation as it is the primary determinant for the inhibition and cGMP-dependent activation of the catalytic domain. Hence, it is critical to understand how CBD-D is allosterically regulated by cGMP. Although the apo versus holo conformational changes of CBD-D have been reported, information on the intermediates of the activation pathway is currently lacking. Here, we employed molecular dynamics simulations to model four key states along the thermodynamic cycle for the cGMP-dependent activation of the PfPKG CBD-D domain. The simulations were compared to NMR data, and they revealed that the PfPKG CBD-D activation pathway samples a compact intermediate in which the N- and C-terminal helices approach the central β-barrel. In addition, by comparing the cGMP-bound active and inactive states, the essential binding interactions that differentiate these states were identified. The identification of structural and dynamical features unique to the cGMP-bound inactive state provides a promising basis to design PfPKG-selective allosteric inhibitors as a viable treatment for malaria.
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Affiliation(s)
- Jinfeng Huang
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Jung Ah Byun
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Philipp Henning
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Friedrich W Herberg
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Choel Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, United States.,Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030, United States.,Center for Drug Discovery, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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4
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Kim C, Sharma R. Cyclic nucleotide selectivity of protein kinase G isozymes. Protein Sci 2020; 30:316-327. [PMID: 33271627 DOI: 10.1002/pro.4008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 11/07/2022]
Abstract
The intrinsic activity of the C-terminal catalytic (C) domain of cyclic guanosine monophosphate (cGMP)-dependent protein kinases (PKG) is inhibited by interactions with the N-terminal regulatory (R) domain. Selective binding of cGMP to cyclic nucleotide binding (CNB) domains within the R-domain disrupts the inhibitory R-C interaction, leading to the release and activation of the C-domain. Affinity measurements of mammalian and plasmodium PKG CNB domains reveal different degrees of cyclic nucleotide affinity and selectivity; the CNB domains adjacent to the C-domain are more cGMP selective and therefore critical for cGMP-dependent activation. Crystal structures of isolated CNB domains in the presence and absence of cyclic nucleotides reveal isozyme-specific contacts that explain cyclic nucleotide selectivity and conformational changes that accompany CNB. Crystal structures of tandem CNB domains identify two types of CNB-mediated dimeric contacts that indicate cGMP-driven reorganization of domain-domain interfaces that include large conformational changes. Here, we review the available structural and functional information of PKG CNB domains that further advance our understanding of cGMP mediated regulation and activation of PKG isozymes.
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Affiliation(s)
- Choel Kim
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Rajesh Sharma
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
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Njila Tchoufack EJ, Hahnfeld L, Pitschelatow G, Bennink S, Pradel G. The endoplasmic reticulum-resident serpentine receptor SR10 has important functions for asexual and sexual blood stage development of Plasmodium falciparum. Mol Biochem Parasitol 2020; 239:111315. [PMID: 32890576 DOI: 10.1016/j.molbiopara.2020.111315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 07/13/2020] [Accepted: 07/28/2020] [Indexed: 11/28/2022]
Abstract
Serpentine receptors (SRs) are transmembrane proteins generally acting as mediators to facilitate the communication between a cell and its environment. At least six putative SR-like proteins are encoded in the genome of the malaria parasite Plasmodium falciparum. For two of them, roles in cell stress control were reported; however, for most of the SR-like proteins the functions are not yet known. In this study, we provide a first phenotypic analysis of the plasmodial SR10. The transmembrane protein is expressed in the asexual and sexual blood stages of P. falciparum. Co-localization and co-immunoprecipitation assays demonstrated an association of SR10 with the endoplasmic reticulum protein ERC. Gene disruption of SR10 leads to impaired intraerythrocytic replication and strongly reduces gametocyte numbers. We thus propose that SR10 is a protein associated with the endoplasmic reticulum that has important functions for asexual and sexual blood stage development.
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Affiliation(s)
| | - Lena Hahnfeld
- Division of Cellular and Applied Infection Biology, Institute of Biology 2, RWTH Aachen University, Aachen, Germany
| | - Georg Pitschelatow
- Division of Cellular and Applied Infection Biology, Institute of Biology 2, RWTH Aachen University, Aachen, Germany
| | - Sandra Bennink
- Division of Cellular and Applied Infection Biology, Institute of Biology 2, RWTH Aachen University, Aachen, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Biology 2, RWTH Aachen University, Aachen, Germany.
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6
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Bellantuono AJ, Dougan KE, Granados‐Cifuentes C, Rodriguez‐Lanetty M. Free‐living and symbiotic lifestyles of a thermotolerant coral endosymbiont display profoundly distinct transcriptomes under both stable and heat stress conditions. Mol Ecol 2019; 28:5265-5281. [DOI: 10.1111/mec.15300] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 10/22/2019] [Accepted: 10/25/2019] [Indexed: 02/06/2023]
Affiliation(s)
| | - Katherine E. Dougan
- Department of Biological Sciences Florida International University Miami FL USA
| | - Camila Granados‐Cifuentes
- Department of Biological Sciences Florida International University Miami FL USA
- Baruch College The City University of New York New York NY USA
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7
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Abstract
Understanding the mechanisms behind host cell invasion by Plasmodium falciparum remains a major hurdle to developing antimalarial therapeutics that target the asexual cycle and the symptomatic stage of malaria. Host cell entry is enabled by a multitude of precisely timed and tightly regulated receptor-ligand interactions. Cyclic nucleotide signaling has been implicated in regulating parasite invasion, and an important downstream effector of the cAMP-signaling pathway is protein kinase A (PKA), a cAMP-dependent protein kinase. There is increasing evidence that P. falciparum PKA (PfPKA) is responsible for phosphorylation of the cytoplasmic domain of P. falciparum apical membrane antigen 1 (PfAMA1) at Ser610, a cAMP-dependent event that is crucial for successful parasite invasion. In the present study, CRISPR-Cas9 and conditional gene deletion (dimerizable cre) technologies were implemented to generate a P. falciparum parasite line in which expression of the catalytic subunit of PfPKA (PfPKAc) is under conditional control, demonstrating highly efficient dimerizable Cre recombinase (DiCre)-mediated gene excision and complete knockdown of protein expression. Parasites lacking PfPKAc show severely reduced growth after one intraerythrocytic growth cycle and are deficient in host cell invasion, as highlighted by live-imaging experiments. Furthermore, PfPKAc-deficient parasites are unable to phosphorylate PfAMA1 at Ser610. This work not only identifies an essential role for PfPKAc in the P. falciparum asexual life cycle but also confirms that PfPKAc is the kinase responsible for phosphorylating PfAMA1 Ser610.IMPORTANCE Malaria continues to present a major global health burden, particularly in low-resource countries. Plasmodium falciparum, the parasite responsible for the most severe form of malaria, causes disease through rapid and repeated rounds of invasion and replication within red blood cells. Invasion into red blood cells is essential for P. falciparum survival, and the molecular events mediating this process have gained much attention as potential therapeutic targets. With no effective vaccine available, and with the emergence of resistance to antimalarials, there is an urgent need for the development of new therapeutics. Our research has used genetic techniques to provide evidence of an essential protein kinase involved in P. falciparum invasion. Our work adds to the current understanding of parasite signaling processes required for invasion, highlighting PKA as a potential drug target to inhibit invasion for the treatment of malaria.
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8
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Uboldi AD, Wilde ML, McRae EA, Stewart RJ, Dagley LF, Yang L, Katris NJ, Hapuarachchi SV, Coffey MJ, Lehane AM, Botte CY, Waller RF, Webb AI, McConville MJ, Tonkin CJ. Protein kinase A negatively regulates Ca2+ signalling in Toxoplasma gondii. PLoS Biol 2018; 16:e2005642. [PMID: 30208022 PMCID: PMC6152992 DOI: 10.1371/journal.pbio.2005642] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 09/24/2018] [Accepted: 08/20/2018] [Indexed: 11/18/2022] Open
Abstract
The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating stages and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is complete to allow for replication to begin is not understood. Here, we show that the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1). Upon genetic depletion of PKAc1 we show that newly invaded parasites exit host cells shortly thereafter, in a perforin-like protein 1 (PLP-1)-dependent fashion. Furthermore, we demonstrate that loss of PKAc1 prevents rapid down-regulation of cytosolic [Ca2+] levels shortly after invasion. We also provide evidence that loss of PKAc1 sensitises parasites to cyclic GMP (cGMP)-induced Ca2+ signalling, thus demonstrating a functional link between cAMP and these other signalling modalities. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity. Central to pathogenesis and infectivity of Toxoplasma and related parasites is their ability to move through tissue, invade host cells, and establish a replicative niche. Ca2+-dependent signalling pathways are important for activating motility, host cell invasion, and egress, yet how this signalling is turned off after invasion is unclear. Here, we show that a cAMP-dependent protein kinase A (PKA) is essential for rapid suppression of Ca2+ signalling upon completion of host cell invasion. Parasites lacking this kinase rapidly invoke an egress program to re-exit host cells, thus preventing the establishment of a stable infection. This finding therefore highlights the first factor required for Toxoplasma (and any related apicomplexan parasite) to switch from invasive to the replicative forms.
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Affiliation(s)
- Alessandro D. Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Mary-Louise Wilde
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Emi A. McRae
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Rebecca J. Stewart
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Laura F. Dagley
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Luning Yang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- School of Medicine, Tsinghua University, Beijing, China
| | - Nicholas J. Katris
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | | | - Michael J. Coffey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Adele M. Lehane
- Research School of Biology, The Australian National University, A.C.T., Australia
| | - Cyrille Y. Botte
- Institute of Advanced Biosciences, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | - Ross F. Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Andrew I. Webb
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia
| | - Christopher J. Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
- * E-mail:
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9
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Bennink S, von Bohl A, Ngwa CJ, Henschel L, Kuehn A, Pilch N, Weißbach T, Rosinski AN, Scheuermayer M, Repnik U, Przyborski JM, Minns AM, Orchard LM, Griffiths G, Lindner SE, Llinás M, Pradel G. A seven-helix protein constitutes stress granules crucial for regulating translation during human-to-mosquito transmission of Plasmodium falciparum. PLoS Pathog 2018; 14:e1007249. [PMID: 30133543 PMCID: PMC6122839 DOI: 10.1371/journal.ppat.1007249] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 09/04/2018] [Accepted: 07/29/2018] [Indexed: 12/16/2022] Open
Abstract
The complex life-cycle of the human malaria parasite Plasmodium falciparum requires a high degree of tight coordination allowing the parasite to adapt to changing environments. One of the major challenges for the parasite is the human-to-mosquito transmission, which starts with the differentiation of blood stage parasites into the transmissible gametocytes, followed by the rapid conversion of the gametocytes into gametes, once they are taken up by the blood-feeding Anopheles vector. In order to pre-adapt to this change of host, the gametocytes store transcripts in stress granules that encode proteins needed for parasite development in the mosquito. Here we report on a novel stress granule component, the seven-helix protein 7-Helix-1. The protein, a homolog of the human stress response regulator LanC-like 2, accumulates in stress granules of female gametocytes and interacts with ribonucleoproteins, such as CITH, DOZI, and PABP1. Malaria parasites lacking 7-Helix-1 are significantly impaired in female gametogenesis and thus transmission to the mosquito. Lack of 7-Helix-1 further leads to a deregulation of components required for protein synthesis. Consistently, inhibitors of translation could mimic the 7-Helix-1 loss-of-function phenotype. 7-Helix-1 forms a complex with the RNA-binding protein Puf2, a translational regulator of the female-specific antigen Pfs25, as well as with pfs25-coding mRNA. In accord, gametocytes deficient of 7-Helix-1 exhibit impaired Pfs25 synthesis. Our data demonstrate that 7-Helix-1 constitutes stress granules crucial for regulating the synthesis of proteins needed for life-cycle progression of Plasmodium in the mosquito vector.
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Affiliation(s)
- Sandra Bennink
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | - Andreas von Bohl
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | - Che J. Ngwa
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | - Leonie Henschel
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | - Andrea Kuehn
- Research Center for Infectious Diseases, University of Würzburg, Würzburg, Germany
| | - Nicole Pilch
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | - Tim Weißbach
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | - Alina N. Rosinski
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
| | | | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway
| | | | - Allen M. Minns
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Lindsey M. Orchard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | | | - Scott E. Lindner
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
- Department of Chemistry & Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, United States of America
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, RWTH Aachen University, Aachen, Germany
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10
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Franz E, Knape MJ, Herberg FW. cGMP Binding Domain D Mediates a Unique Activation Mechanism in Plasmodium falciparum PKG. ACS Infect Dis 2018; 4:415-423. [PMID: 29251493 DOI: 10.1021/acsinfecdis.7b00222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
cGMP-dependent protein kinase from Plasmodium falciparum ( PfPKG) plays a crucial role in the sexual as well as the asexual proliferation of this human malaria causing parasite. However, function and regulation of PfPKG are largely unknown. Previous studies showed that the domain organization of PfPKG significantly differs from human PKG ( hPKG) and indicated a critical role of the cyclic nucleotide binding domain D (CNB-D). We identified a novel mechanism, where the CNB-D controls activation and regulation of the parasite specific protein kinase. Here, kinase activity is not dependent on a pseudosubstrate autoinhibitory sequence (IS), as reported for human PKG. A construct lacking the putative IS and containing only the CNB-D and the catalytic domain is inactive in the absence of cGMP and can efficiently be activated with cGMP. On the basis of structural evidence, we describe a regulatory mechanism, whereby cGMP binding to CNB-D induces a conformational change involving the αC-helix of the CNB-D. The inactive state is defined by a unique interaction between Asp597 of the catalytic domain and Arg528 of the αC-helix. The same arginine (R528), however, stabilizes cGMP binding by interacting with Tyr480 of the phosphate binding cassette (PBC). This represents the active state of PfPKG. Our results unveil fundamental differences in the activation mechanism between PfPKG and hPKG, building the basis for the development of strategies for targeted drug design in fighting malaria.
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Affiliation(s)
- Eugen Franz
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Matthias J. Knape
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Friedrich W. Herberg
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
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11
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Rojas-Pirela M, Rigden DJ, Michels PA, Cáceres AJ, Concepción JL, Quiñones W. Structure and function of Per-ARNT-Sim domains and their possible role in the life-cycle biology of Trypanosoma cruzi. Mol Biochem Parasitol 2017; 219:52-66. [PMID: 29133150 DOI: 10.1016/j.molbiopara.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/12/2017] [Accepted: 11/02/2017] [Indexed: 02/07/2023]
Abstract
Per-ARNT-Sim (PAS) domains of proteins play important roles as modules for signalling and cellular regulation processes in widely diverse organisms such as Archaea, Bacteria, protists, plants, yeasts, insects and vertebrates. These domains are present in many proteins where they are used as sensors of stimuli and modules for protein interactions. Characteristically, they can bind a broad spectrum of molecules. Such binding causes the domain to trigger a specific cellular response or to make the protein containing the domain susceptible to responding to additional physical or chemical signals. Different PAS proteins have the ability to sense redox potential, light, oxygen, energy levels, carboxylic acids, fatty acids and several other stimuli. Such proteins have been found to be involved in cellular processes such as development, virulence, sporulation, adaptation to hypoxia, circadian cycle, metabolism and gene regulation and expression. Our analysis of the genome of different kinetoplastid species revealed the presence of PAS domains also in different predicted kinases from these protists. Open-reading frames coding for these PAS-kinases are unusually large. In addition, the products of these genes appear to contain in their structure combinations of domains uncommon in other eukaryotes. The physiological significance of PAS domains in these parasites, specifically in Trypanosoma cruzi, is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, Scotland, United Kingdom
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela.
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12
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Jia Y, Marq JB, Bisio H, Jacot D, Mueller C, Yu L, Choudhary J, Brochet M, Soldati-Favre D. Crosstalk between PKA and PKG controls pH-dependent host cell egress of Toxoplasma gondii. EMBO J 2017; 36:3250-3267. [PMID: 29030485 PMCID: PMC5666616 DOI: 10.15252/embj.201796794] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 09/08/2017] [Accepted: 09/12/2017] [Indexed: 12/27/2022] Open
Abstract
Toxoplasma gondii encodes three protein kinase A catalytic (PKAc1-3) and one regulatory (PKAr) subunits to integrate cAMP-dependent signals. Here, we show that inactive PKAc1 is maintained at the parasite pellicle by interacting with acylated PKAr. Either a conditional knockdown of PKAr or the overexpression of PKAc1 blocks parasite division. Conversely, down-regulation of PKAc1 or stabilisation of a dominant-negative PKAr isoform that does not bind cAMP triggers premature parasite egress from infected cells followed by serial invasion attempts leading to host cell lysis. This untimely egress depends on host cell acidification. A phosphoproteome analysis suggested the interplay between cAMP and cGMP signalling as PKAc1 inactivation changes the phosphorylation profile of a putative cGMP-phosphodiesterase. Concordantly, inhibition of the cGMP-dependent protein kinase G (PKG) blocks egress induced by PKAc1 inactivation or environmental acidification, while a cGMP-phosphodiesterase inhibitor circumvents egress repression by PKAc1 or pH neutralisation. This indicates that pH and PKAc1 act as balancing regulators of cGMP metabolism to control egress. These results reveal a crosstalk between PKA and PKG pathways to govern egress in T. gondii.
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Affiliation(s)
- Yonggen Jia
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Jean-Baptiste Marq
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Hugo Bisio
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Damien Jacot
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Christina Mueller
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Lu Yu
- Proteomic Mass-spectrometry Team, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Jyoti Choudhary
- Proteomic Mass-spectrometry Team, Wellcome Trust Sanger Institute, Hinxton, UK
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva 4, Switzerland
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13
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Yi Y, de Jong A, Frenzel E, Kuipers OP. Comparative Transcriptomics of Bacillus mycoides Strains in Response to Potato-Root Exudates Reveals Different Genetic Adaptation of Endophytic and Soil Isolates. Front Microbiol 2017; 8:1487. [PMID: 28824604 PMCID: PMC5543090 DOI: 10.3389/fmicb.2017.01487] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/24/2017] [Indexed: 12/11/2022] Open
Abstract
Plant root secreted compounds alter the gene expression of associated microorganisms by acting as signal molecules that either stimulate or repel the interaction with beneficial or harmful species, respectively. However, it is still unclear whether two distinct groups of beneficial bacteria, non-plant-associated (soil) strains and plant-associated (endophytic) strains, respond uniformly or variably to the exposure with root exudates. Therefore, Bacillus mycoides, a potential biocontrol agent and plant growth-promoting bacterium, was isolated from the endosphere of potatoes and from soil of the same geographical region. Confocal fluorescence microscopy of plants inoculated with GFP-tagged B. mycoides strains showed that the endosphere isolate EC18 had a stronger plant colonization ability and competed more successfully for the colonization sites than the soil isolate SB8. To dissect these phenotypic differences, the genomes of the two strains were sequenced and the transcriptome response to potato root exudates was compared. The global transcriptome profiles evidenced that the endophytic isolate responded more pronounced than the soil-derived isolate and a higher number of significant differentially expressed genes were detected. Both isolates responded with the alteration of expression of an overlapping set of genes, which had previously been reported to be involved in plant–microbe interactions; including organic substance metabolism, oxidative reduction, and transmembrane transport. Notably, several genes were specifically upregulated in the endosphere isolate EC18, while being oppositely downregulated in the soil isolate SB8. These genes mainly encoded membrane proteins, transcriptional regulators or were involved in amino acid metabolism and biosynthesis. By contrast, several genes upregulated in the soil isolate SB8 and downregulated in the endosphere isolate EC18 were related to sugar transport, which might coincide with the different nutrient availability in the two environments. Altogether, the presented transcriptome profiles provide highly improved insights into the life strategies of plant-associated endophytes and soil isolates of B. mycoides.
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Affiliation(s)
- Yanglei Yi
- Molecular Genetics Department, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Anne de Jong
- Molecular Genetics Department, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Elrike Frenzel
- Molecular Genetics Department, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
| | - Oscar P Kuipers
- Molecular Genetics Department, Groningen Biomolecular Sciences and Biotechnology Institute, University of GroningenGroningen, Netherlands
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14
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Soni R, Sharma D, Rai P, Sharma B, Bhatt TK. Signaling Strategies of Malaria Parasite for Its Survival, Proliferation, and Infection during Erythrocytic Stage. Front Immunol 2017; 8:349. [PMID: 28400771 PMCID: PMC5368685 DOI: 10.3389/fimmu.2017.00349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/10/2017] [Indexed: 12/22/2022] Open
Abstract
Irrespective of various efforts, malaria persist the most debilitating effect in terms of morbidity and mortality. Moreover, the existing drugs are also vulnerable to the emergence of drug resistance. To explore the potential targets for designing the most effective antimalarial therapies, it is required to focus on the facts of biochemical mechanism underlying the process of parasite survival and disease pathogenesis. This review is intended to bring out the existing knowledge about the functions and components of the major signaling pathways such as kinase signaling, calcium signaling, and cyclic nucleotide-based signaling, serving the various aspects of the parasitic asexual stage and highlighted the Toll-like receptors, glycosylphosphatidylinositol-mediated signaling, and molecular events in cytoadhesion, which elicit the host immune response. This discussion will facilitate a look over essential components for parasite survival and disease progression to be implemented in discovery of novel antimalarial drugs and vaccines.
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Affiliation(s)
- Rani Soni
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Drista Sharma
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Praveen Rai
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Bhaskar Sharma
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
| | - Tarun K Bhatt
- Department of Biotechnology, School of Life sciences, Central University of Rajasthan , Ajmer , India
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15
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Feng H, Gupta B, Wang M, Zheng W, Zheng L, Zhu X, Yang Y, Fang Q, Luo E, Fan Q, Tsuboi T, Cao Y, Cui L. Genetic diversity of transmission-blocking vaccine candidate Pvs48/45 in Plasmodium vivax populations in China. Parasit Vectors 2015; 8:615. [PMID: 26627683 PMCID: PMC4665908 DOI: 10.1186/s13071-015-1232-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/26/2015] [Indexed: 11/16/2022] Open
Abstract
Background The male gamete fertilization factor P48/45 in malaria parasites is a prime transmission-blocking vaccine (TBV) candidate. Efforts to develop antimalarial vaccines are often thwarted by genetic diversity of the target antigens. Here we evaluated the genetic diversity of Pvs48/45 gene in global Plasmodium vivax populations. Methods We determined 200 Pvs48/45 sequences collected from temperate and subtropical parasite populations in China. Population genetic and evolutionary analyses were performed to determine the levels of genetic diversity, potential signature of selection, and population differentiation. Results Analysis of the Pvs48/45 sequences from 200 P. vivax parasites collected in a temperate and a tropical region revealed a low level of genetic diversity (π = 0.0012) with 14 single nucleotide polymorphisms, of which 11 were nonsynonymous. Analysis of 344 Pvs48/45 sequences from nine worldwide P. vivax populations detected a total of 38 haplotypes, of which 13 haplotypes were present only once. Multiple tests for selection confirmed a signature of positive selection on Pvs48/45 with selection skewed to the second cysteine domain. Haplotype network analysis and Wright’s fixation index showed large geographical differentiation with the presence of continent-or region-specific mutations in this gene. Conclusions Pvs48/45 displays low levels of genetic diversity with the presence of region-specific mutations. Some of the mutations may be potential epitope targets based on their positions in the predicted structure, highlighting the need for future evaluation of these mutations in designing Pvs48/45-based TBV. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1232-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hui Feng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Bhavna Gupta
- Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA, 16802, USA.
| | - Meilian Wang
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Wenqi Zheng
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Li Zheng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Yimei Yang
- Department of Parasitology, College of Basic Medical Sciences, Dali Medical College, Dali, Yunnan, China.
| | - Qiang Fang
- Department of Parasitology, Bengbu Medical College, Anhui, China.
| | - Enjie Luo
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China.
| | - Takafumi Tsuboi
- Cell-free Science and Technology Research Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China. .,Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA, 16802, USA.
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16
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Franz E, Kim JJ, Schneider O, Bertinetti D, Kim C, Herberg FW. The role of a parasite-specific D-site in activation of Plasmodium falciparum cGMP-dependent protein kinase. BMC Pharmacol Toxicol 2015. [PMCID: PMC4565114 DOI: 10.1186/2050-6511-16-s1-a51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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17
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A Putative Non-Canonical Ras-Like GTPase from P. falciparum: Chemical Properties and Characterization of the Protein. PLoS One 2015; 10:e0140994. [PMID: 26540393 PMCID: PMC4634863 DOI: 10.1371/journal.pone.0140994] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/02/2015] [Indexed: 12/16/2022] Open
Abstract
During its development the malaria parasite P. falciparum has to adapt to various different environmental contexts. Key cellular mechanisms involving G-protein coupled signal transduction chains are assumed to act at these interfaces. Heterotrimeric G-proteins are absent in Plasmodium. We here describe the first cloning and expression of a putative, non-canonical Ras-like G protein (acronym PfG) from Plasmodium. PfG reveals an open reading frame of 2736 bp encoding a protein of 912 amino acids with a theoretical pI of 8.68 and a molecular weight of 108.57 kDa. Transcript levels and expression are significantly increased in the erythrocytic phase in particular during schizont and gametocyte formation. Most notably, PfG has GTP binding capacity and GTPase activity due to an EngA2 domain present in small Ras-like GTPases in a variety of Bacillus species and Mycobacteria. By contrast, plasmodial PfG is divergent from any human alpha-subunit. PfG was expressed in E. coli as a histidine-tagged fusion protein and was stable only for 3.5 hours. Purification was only possible under native conditions by Nickel-chelate chromatography and subsequent separation by Blue Native PAGE. Binding of a fluorescent GTP analogue BODIPY® FL guanosine 5’O-(thiotriphosphate) was determined by fluorescence emission. Mastoparan stimulated GTP binding in the presence of Mg2+. GTPase activity was determined colorimetrically. Activity expressed as absolute fluorescence was 50% higher for the human paralogue than the activity of the parasitic enzyme. The PfG protein is expressed in the erythrocytic stages and binds GTP after immunoprecipitation. Immunofluorescence using specific antiserum suggests that PfG localizes to the parasite cytosol. The current data suggest that the putitative, Ras-like G-protein might be involved in a non-canonical signaling pathway in Plasmodium. Research on the function of PfG with respect to pathogenesis and antimalarial chemotherapy is currently under way.
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18
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Ramdani G, Naissant B, Thompson E, Breil F, Lorthiois A, Dupuy F, Cummings R, Duffier Y, Corbett Y, Mercereau-Puijalon O, Vernick K, Taramelli D, Baker DA, Langsley G, Lavazec C. cAMP-Signalling Regulates Gametocyte-Infected Erythrocyte Deformability Required for Malaria Parasite Transmission. PLoS Pathog 2015; 11:e1004815. [PMID: 25951195 PMCID: PMC4423841 DOI: 10.1371/journal.ppat.1004815] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 03/13/2015] [Indexed: 12/31/2022] Open
Abstract
Blocking Plasmodium falciparum transmission to mosquitoes has been designated a strategic objective in the global agenda of malaria elimination. Transmission is ensured by gametocyte-infected erythrocytes (GIE) that sequester in the bone marrow and at maturation are released into peripheral blood from where they are taken up during a mosquito blood meal. Release into the blood circulation is accompanied by an increase in GIE deformability that allows them to pass through the spleen. Here, we used a microsphere matrix to mimic splenic filtration and investigated the role of cAMP-signalling in regulating GIE deformability. We demonstrated that mature GIE deformability is dependent on reduced cAMP-signalling and on increased phosphodiesterase expression in stage V gametocytes, and that parasite cAMP-dependent kinase activity contributes to the stiffness of immature gametocytes. Importantly, pharmacological agents that raise cAMP levels in transmissible stage V gametocytes render them less deformable and hence less likely to circulate through the spleen. Therefore, phosphodiesterase inhibitors that raise cAMP levels in P. falciparum infected erythrocytes, such as sildenafil, represent new candidate drugs to block transmission of malaria parasites. Malaria transmission is ensured by deformable mature gametocyte-infected erythrocytes being taken up when a mosquito bites. Non-deformable immature gametocyte stages are sequestered in the bone marrow, as their lack of deformability would lead to their splenic clearance. In the present study, we apply nano-filtration technology to mimic splenic retention and demonstrate that deformability of transmissible mature stage V gametocytes is regulated by parasite cyclic AMP-dependent kinase signalling. Importantly, when we used drugs to raise cAMP levels we render transmissible mature gametocytes as stiff as non-transmissible gametocytes. In contrast, when we inhibit the cAMP-dependent kinase we render immature gametocytes more deformable. Thus, by two different approaches we confirm that the drop in cAMP levels in mature gametocytes leads to an increase in their deformability and hence more likely to circulate through the spleen. Our molecular observations have the potential to be translated into therapies for blocking malaria transmission by demonstrating that raising cAMP levels with sildenafil also known as “Viagra” renders mature gametocytes rigid. These findings provide the proof of principle that deformability of circulating gametocytes is targetable by pharmacological agents and as such, it provides a novel approach to prevent the spread of parasites. PDE inhibitors therefore represent novel drug leads potentially capable of blocking transmission and improving the worldwide fight to eliminate malaria from the human population.
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Affiliation(s)
- Ghania Ramdani
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Bernina Naissant
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
- Laboratoire de Biologie de la Transmission de Plasmodium, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
| | - Eloise Thompson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Florence Breil
- Institut Pasteur, Unité de Génétique et Génomique des Insectes Vecteurs, CNRS URA 3012, Paris, France
| | - Audrey Lorthiois
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
- Laboratoire de Biologie de la Transmission de Plasmodium, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
- Institut Pasteur, Unité de Génétique et Génomique des Insectes Vecteurs, CNRS URA 3012, Paris, France
| | - Florian Dupuy
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
- Laboratoire de Biologie de la Transmission de Plasmodium, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
| | - Ross Cummings
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Yoann Duffier
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
- Laboratoire de Biologie de la Transmission de Plasmodium, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
| | - Yolanda Corbett
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università di Milano, Milano, Italy
| | | | - Kenneth Vernick
- Institut Pasteur, Unité de Génétique et Génomique des Insectes Vecteurs, CNRS URA 3012, Paris, France
| | - Donatella Taramelli
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università di Milano, Milano, Italy
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
- * E-mail: (GL); (CL)
| | - Catherine Lavazec
- Inserm U1016, CNRS UMR8104, Institut Cochin, Paris, France
- Laboratoire de Biologie de la Transmission de Plasmodium, Faculté de Médicine, Université Paris Descartes—Sorbonne Paris Cité, Paris, France
- Institut Pasteur, Unité de Génétique et Génomique des Insectes Vecteurs, CNRS URA 3012, Paris, France
- * E-mail: (GL); (CL)
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19
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Shanks GD. Hypothesis: dynamics of classical malaria epidemics show Plasmodium falciparum's survival strategy. Am J Trop Med Hyg 2015; 92:561-4. [PMID: 25624407 PMCID: PMC4350549 DOI: 10.4269/ajtmh.14-0541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/07/2014] [Indexed: 11/07/2022] Open
Abstract
Areas of marginal transmission can generate enormous lethal falciparum malaria epidemics when factors favoring the parasite shift only slightly. Although usually described in terms of vectorial capacity, medical scientists working in India in the early 20th century came to the conclusion that "an epidemic of relapses" was the key triggering event of malaria epidemics. This explanation has been largely discarded, because the biology of Plasmodium falciparum recrudescence has since been differentiated from P. vivax relapse. Using data from the Punjab in 1908 and Ceylon in 1934-1935, the genesis of malaria epidemics has been re-examined to inform current control efforts. The epidemics were focused geographically depending on recent rainfall or drought. Epidemics arose very suddenly and simultaneously in several places. Malaria spleen surveys indicated very little recent malaria transmission, and blood smears showed very few gametocytes just before the epidemic. Population stress as indicated by high grain prices because of a poor harvest caused by drought the previous year was a risk factor for malaria epidemics. Although increased female Anopheline survival because of increased humidity played an important part in the magnification of the epidemic, it does not explain its genesis. Human population stress triggering a shift toward gametocytogenesis is hypothesized as the key initiation factor for malaria epidemics. Its evolutionary significance may be that it allows the parasite to match the tropical agricultural cycle.
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Affiliation(s)
- G Dennis Shanks
- Australian Army Malaria Institute, Enoggera, Australia; School of Population Health, University of Queensland, Brisbane, Australia; Department of Zoology, University of Oxford, Oxford, United Kingdom
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20
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Kim JJ, Flueck C, Franz E, Sanabria-Figueroa E, Thompson E, Lorenz R, Bertinetti D, Baker DA, Herberg FW, Kim C. Crystal structures of the carboxyl cGMP binding domain of the Plasmodium falciparum cGMP-dependent protein kinase reveal a novel capping triad crucial for merozoite egress. PLoS Pathog 2015; 11:e1004639. [PMID: 25646845 PMCID: PMC4412288 DOI: 10.1371/journal.ppat.1004639] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 12/20/2014] [Indexed: 01/05/2023] Open
Abstract
The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is a key regulator across the malaria parasite life cycle. Little is known about PfPKG’s activation mechanism. Here we report that the carboxyl cyclic nucleotide binding domain functions as a “gatekeeper” for activation by providing the highest cGMP affinity and selectivity. To understand the mechanism, we have solved its crystal structures with and without cGMP at 2.0 and 1.9 Å, respectively. These structures revealed a PfPKG-specific capping triad that forms upon cGMP binding, and disrupting the triad reduces kinase activity by 90%. Furthermore, mutating these residues in the parasite prevents blood stage merozoite egress, confirming the essential nature of the triad in the parasite. We propose a mechanism of activation where cGMP binding allosterically triggers the conformational change at the αC-helix, which bridges the regulatory and catalytic domains, causing the capping triad to form and stabilize the active conformation. Malaria causes up to a million fatalities per year worldwide. Most of these deaths are caused by Plasmodium falciparum, which has a complex life cycle in both humans and mosquitoes. One key regulator of this process is P. falciparum cGMP-dependent protein kinase (PfPKG), the main effector of the cGMP-signaling pathway. Specifically blocking this kinase stops both replication and transmission of the parasites, suggesting that PfPKG is a promising drug target. Here we identified the carboxyl cGMP-binding domain of PfPKG serving as a gatekeeper for activation of the entire kinase by having the highest affinity and selectivity for cGMP. High-resolution crystal structures with and without cGMP allowed us to identify a novel cGMP capping triad that dynamically forms upon binding cGMP and stabilizes the activated conformation. Mutation of the capping triad forming residues not only reduces its kinase activity, but also prevents blood stage merozoite egress, demonstrating its crucial role in PfPKG activation.
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Affiliation(s)
- Jeong Joo Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Eugen Franz
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | | | - Eloise Thompson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin Lorenz
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - Daniela Bertinetti
- Department of Biochemistry, University of Kassel, Kassel, Hesse, Germany
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Choel Kim
- Department of Pharmacology, Baylor College of Medicine, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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21
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Woodring JL, Pollastri MP. Inhibitors of Protozoan Phosphodiesterases as Potential Therapeutic Approaches for Tropical Diseases. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/9783527682348.ch12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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22
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Kumar P, Tripathi A, Ranjan R, Halbert J, Gilberger T, Doerig C, Sharma P. Regulation of Plasmodium falciparum development by calcium-dependent protein kinase 7 (PfCDPK7). J Biol Chem 2014; 289:20386-95. [PMID: 24895132 DOI: 10.1074/jbc.m114.561670] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Second messengers such as phosphoinositides and calcium are known to control diverse processes involved in the development of malaria parasites. However, the underlying molecular mechanisms and pathways need to be unraveled, which may be achieved by understanding the regulation of effectors of these second messengers. Calcium-dependent protein kinase (CDPK) family members regulate diverse parasitic processes. Because CDPKs are absent from the host, these kinases are considered as potential drug targets. We have dissected the function of an atypical CDPK from Plasmodium falciparum, PfCDPK7. The domain architecture of PfCDPK7 is very different from that of other CDPKs; it has a pleckstrin homology domain adjacent to the kinase domain and two calcium-binding EF-hands at its N terminus. We demonstrate that PfCDPK7 interacts with PI(4,5)P2 via its pleckstrin homology domain, which may guide its subcellular localization. Disruption of PfCDPK7 caused a marked reduction in the growth of the blood stage parasites, as maturation of rings to trophozoites was markedly stalled. In addition, parasite proliferation was significantly attenuated. These findings shed light on an important role for PfCDPK7 in the erythrocytic asexual cycle of malaria parasites.
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Affiliation(s)
- Praveen Kumar
- From the Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi 110067, India
| | - Anuj Tripathi
- From the Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi 110067, India
| | - Ravikant Ranjan
- From the Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi 110067, India
| | - Jean Halbert
- the Inserm-EPFL Joint Laboratory, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Tim Gilberger
- the Department of Pathology and Molecular Medicine, M.G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada, the Bernhard-Nocht-Institute for Tropical Medicine, 20359 Hamburg, Germany, and
| | - Christian Doerig
- the Inserm-EPFL Joint Laboratory, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland, the Department of Microbiology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Pushkar Sharma
- From the Eukaryotic Gene Expression Laboratory, National Institute of Immunology, New Delhi 110067, India,
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Brochet M, Collins MO, Smith TK, Thompson E, Sebastian S, Volkmann K, Schwach F, Chappell L, Gomes AR, Berriman M, Rayner JC, Baker DA, Choudhary J, Billker O. Phosphoinositide metabolism links cGMP-dependent protein kinase G to essential Ca²⁺ signals at key decision points in the life cycle of malaria parasites. PLoS Biol 2014; 12:e1001806. [PMID: 24594931 PMCID: PMC3942320 DOI: 10.1371/journal.pbio.1001806] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/23/2014] [Indexed: 12/04/2022] Open
Abstract
Many critical events in the Plasmodium life cycle rely on the controlled release of Ca²⁺ from intracellular stores to activate stage-specific Ca²⁺-dependent protein kinases. Using the motility of Plasmodium berghei ookinetes as a signalling paradigm, we show that the cyclic guanosine monophosphate (cGMP)-dependent protein kinase, PKG, maintains the elevated level of cytosolic Ca²⁺ required for gliding motility. We find that the same PKG-dependent pathway operates upstream of the Ca²⁺ signals that mediate activation of P. berghei gametocytes in the mosquito and egress of Plasmodium falciparum merozoites from infected human erythrocytes. Perturbations of PKG signalling in gliding ookinetes have a marked impact on the phosphoproteome, with a significant enrichment of in vivo regulated sites in multiple pathways including vesicular trafficking and phosphoinositide metabolism. A global analysis of cellular phospholipids demonstrates that in gliding ookinetes PKG controls phosphoinositide biosynthesis, possibly through the subcellular localisation or activity of lipid kinases. Similarly, phosphoinositide metabolism links PKG to egress of P. falciparum merozoites, where inhibition of PKG blocks hydrolysis of phosphatidylinostitol (4,5)-bisphosphate. In the face of an increasing complexity of signalling through multiple Ca²⁺ effectors, PKG emerges as a unifying factor to control multiple cellular Ca²⁺ signals essential for malaria parasite development and transmission.
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Affiliation(s)
- Mathieu Brochet
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Mark O. Collins
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Terry K. Smith
- Schools of Biology and Chemistry, Biomedical Sciences Research Complex, The North Haugh, The University of Saint Andrews, St. Andrews, Fife United Kingdom
| | - Eloise Thompson
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sarah Sebastian
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Katrin Volkmann
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Frank Schwach
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Lia Chappell
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Ana Rita Gomes
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Matthew Berriman
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Julian C. Rayner
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Jyoti Choudhary
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Oliver Billker
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
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24
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Collins CR, Hackett F, Strath M, Penzo M, Withers-Martinez C, Baker DA, Blackman MJ. Malaria parasite cGMP-dependent protein kinase regulates blood stage merozoite secretory organelle discharge and egress. PLoS Pathog 2013; 9:e1003344. [PMID: 23675297 PMCID: PMC3649973 DOI: 10.1371/journal.ppat.1003344] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/22/2013] [Indexed: 11/19/2022] Open
Abstract
The malaria parasite replicates within an intraerythrocytic parasitophorous vacuole (PV). Eventually, in a tightly regulated process called egress, proteins of the PV and intracellular merozoite surface are modified by an essential parasite serine protease called PfSUB1, whilst the enclosing PV and erythrocyte membranes rupture, releasing merozoites to invade fresh erythrocytes. Inhibition of the Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) prevents egress, but the underlying mechanism is unknown. Here we show that PfPKG activity is required for PfSUB1 discharge into the PV, as well as for release of distinct merozoite organelles called micronemes. Stimulation of PfPKG by inhibiting parasite phosphodiesterase activity induces premature PfSUB1 discharge and egress of developmentally immature, non-invasive parasites. Our findings identify the signalling pathway that regulates PfSUB1 function and egress, and raise the possibility of targeting PfPKG or parasite phosphodiesterases in therapeutic approaches to dysregulate critical protease-mediated steps in the parasite life cycle.
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Affiliation(s)
- Christine R. Collins
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Fiona Hackett
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Malcolm Strath
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | - Maria Penzo
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
| | | | - David A. Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael J. Blackman
- Division of Parasitology, MRC National Institute for Medical Research, Mill Hill, London, United Kingdom
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25
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Peatey CL, Dixon MWA, Gardiner DL, Trenholme KR. Temporal evaluation of commitment to sexual development in Plasmodium falciparum. Malar J 2013; 12:134. [PMID: 23607486 PMCID: PMC3659030 DOI: 10.1186/1475-2875-12-134] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 04/12/2013] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND The production of gametocytes is essential for transmission of malaria parasites from the mammalian host to the mosquito vector. However the process by which the asexual blood-stage parasite undergoes commitment to sexual development is not well understood. This process is known to be sensitive to environmental stimuli and it has been suggested that a G protein dependent system may mediate the switch, but there is little evidence that the Plasmodium falciparum genome encodes heterotrimeric G proteins. Previous studies have indicated that the malaria parasite can interact with endogenous erythrocyte G proteins, and other components of the cyclic nucleotide pathway have been identified in P. falciparum. Also, the polypeptide cholera toxin, which induces commitment to gametocytogenesis is known to catalyze the ADP-ribosylation of the α(s) class of heterotrimeric G protein α subunits in mammalian systems has been reported to detect a number of G(α) subunits in P. falciparum-infected red cells. METHODS Cholera toxin and Mas 7 (a structural analogue of Mastoparan) were used to assess the role played by putative G protein signalling in the commitment process, both are reported to interact with different components of classical Gas and Gai/o signalling pathways. Their ability to induce gametocyte production in the transgenic P. falciparum line Pfs16-GFP was determined and downstream effects on the secondary messenger cAMP measured. RESULTS Treatment of parasite cultures with either cholera toxin or MAS 7 resulted in increased gametocyte production, but only treatment with MAS 7 resulted in a significant increase in cAMP levels. This indicates that MAS 7 acts either directly or indirectly on the P. falciparum adenylyl cyclase. CONCLUSION The observation that cholera toxin treatment did not affect cAMP levels indicates that while addition of cholera toxin does increase gametocytogenesis the method by which it induces increased commitment is not immediately obvious, except that is unlikely to be via heterotrimeric G proteins.
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Affiliation(s)
- Christopher L Peatey
- Malaria Biology Laboratory, Queensland Institute of Medical Research, 300 Herston Rd, Herston, QLD 4006, Australia
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26
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Hartmann A, Arroyo-Olarte RD, Imkeller K, Hegemann P, Lucius R, Gupta N. Optogenetic modulation of an adenylate cyclase in Toxoplasma gondii demonstrates a requirement of the parasite cAMP for host-cell invasion and stage differentiation. J Biol Chem 2013; 288:13705-17. [PMID: 23525100 DOI: 10.1074/jbc.m113.465583] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND cAMP research in intracellular parasites remains underappreciated, and it requires a specific method for cyclic nucleotide regulation. RESULTS Optogenetic induction of cAMP in T. gondii affects host-cell invasion, stage-specific expression, and parasite differentiation. The underlying method allows a versatile control of parasite cAMP. CONCLUSIONS Optogenetic parasite strains offer valuable tools for dissecting cAMP-mediated processes. SIGNIFICANCE The method is applicable to other gene-tractable intertwined systems. Successful infection and transmission of the obligate intracellular parasite Toxoplasma gondii depends on its ability to switch between fast-replicating tachyzoite (acute) and quiescent bradyzoite (chronic) stages. Induction of cAMP in the parasitized host cells has been proposed to influence parasite differentiation. It is not known whether the parasite or host cAMP is required to drive this phenomenon. Other putative roles of cAMP for the parasite biology also remain to be identified. Unequivocal research on cAMP-mediated signaling in such intertwined systems also requires a method for an efficient and spatial control of the cAMP pool in the pathogen or in the enclosing host cell. We have resolved these critical concerns by expressing a photoactivated adenylate cyclase that allows light-sensitive control of the parasite or host-cell cAMP. Using this method, we reveal multiple roles of the parasite-derived cAMP in host-cell invasion, stage-specific expression, and asexual differentiation. An optogenetic method provides many desired advantages such as: (i) rapid, transient, and efficient cAMP induction in extracellular/intracellular and acute/chronic stages; (ii) circumvention of the difficulties often faced in cultures, i.e. poor diffusion, premature degradation, steady activation, and/or pleiotropic effects of cAMP agonists and antagonists; (iii) genetically encoded enzyme expression, thus inheritable to the cell progeny; and (iv) conditional and spatiotemporal control of cAMP levels. Importantly, a successful optogenetic application in Toxoplasma also illustrates its wider utility to study cAMP-mediated signaling in other genetically amenable two-organism systems such as in symbiotic and pathogen-host models.
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Affiliation(s)
- Anne Hartmann
- Departments of Molecular Parasitology, Humboldt University, 10115 Berlin, Germany
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27
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Haste NM, Talabani H, Doo A, Merckx A, Langsley G, Taylor SS. Exploring the Plasmodium falciparum cyclic-adenosine monophosphate (cAMP)-dependent protein kinase (PfPKA) as a therapeutic target. Microbes Infect 2012; 14:838-50. [PMID: 22626931 PMCID: PMC3967591 DOI: 10.1016/j.micinf.2012.05.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/01/2012] [Accepted: 05/02/2012] [Indexed: 11/22/2022]
Abstract
One of the prototype mammalian kinases is PKA and various roles have been defined for PKA in malaria pathogenesis. The recently described phospho-proteomes of Plasmodium falciparum introduced a great volume of phospho-peptide data for both basic research and identification of new anti-malaria therapeutic targets. We discuss the importance of phosphorylations detected in vivo at different sites in the parasite R and C subunits of PKA and highlight the inhibitor sites in the parasite R subunit. The N-terminus of the parasite R subunit is predicted to be very flexible and we propose that phosphorylation at multiple sites in this region likely represent docking sites for interactions with other proteins, such as 14-3-3. The most significant observation when the P. falciparum C subunit is compared to mammalian C isoforms is lack of phosphorylation at a key site tail implying that parasite kinase activity is not regulated so tightly as mammalian PKA. Phosphorylation at sites in the activation loop could be mediating a number of processes from regulating parasite kinase activity, to mediating docking of other proteins. The important differences between Plasmodium and mammalian PKA isoforms that indicate the parasite kinase is a valid anti-malaria therapeutic target.
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Affiliation(s)
- Nina M. Haste
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla, CA 92093-0687, USA
| | - Hana Talabani
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes Cité Sorbonne, Paris, France
| | - Alex Doo
- Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093-0654, USA
| | - Anais Merckx
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes Cité Sorbonne, Paris, France
- Faculté des Sciences Pharmaceutiques et Biologiques, UMR 216-IRD, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Gordon Langsley
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes Cité Sorbonne, Paris, France
| | - Susan S. Taylor
- Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093-0654, USA
- Department of Pharmacology, University of California-San Diego, La Jolla, CA 92093-0654, USA
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28
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Touré A, Langsley G, Egée S. Spermatozoa and Plasmodium zoites: the same way to invade oocyte and host cells? Microbes Infect 2012; 14:874-9. [PMID: 22561468 DOI: 10.1016/j.micinf.2012.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/24/2012] [Accepted: 04/25/2012] [Indexed: 11/26/2022]
Abstract
Cell movement or motility is essential for a large variety of processes. Fertilization and host cells invasion by parasites are among the mostly studied models so far. Body of evidences into the literature raises the question that common mechanisms may be found in the sequential events that lead to cell motility in these two particular models. This short review aims at highlighting these common features by comparing knowledge on motile forms of Plasmodium falciparum and one of the best known motile cell namely the spermatozoa. Emphasis will be done on the substantial changes affecting the biochemical, electrophysiological and functional properties of both models.
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Affiliation(s)
- Aminata Touré
- Institut Cochin INSERM U1016, Sorbonne Paris Cité, Paris 75014, France.
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29
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Liu Z, Miao J, Cui L. Gametocytogenesis in malaria parasite: commitment, development and regulation. Future Microbiol 2012; 6:1351-69. [PMID: 22082293 DOI: 10.2217/fmb.11.108] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Malaria parasites have evolved a complicated life cycle alternating between two hosts. Gametocytes are produced in the vertebrate hosts and are obligatory for natural transmission of the parasites through mosquito vectors. The mechanism of sexual development in Plasmodium has been the focus of extensive studies. In the postgenomic era, the advent of genome-wide analytical tools and genetic manipulation technology has enabled rapid advancement of our knowledge in this area. Patterns of gene expression during sexual development, molecular distinction of the two sexes, and mechanisms underlying subsequent formation of gametes and their fertilization have been progressively elucidated. However, the triggers and mechanism of sexual development remain largely unknown. This article provides an update of our understanding of the molecular and cellular events associated with the decision for commitment to sexual development and regulation of gene expression during gametocytogenesis. Insights into the molecular mechanisms of gametocyte development are essential for designing proper control strategies for interruption of malaria transmission and ultimate elimination.
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Affiliation(s)
- Zhenyu Liu
- Department of Entomology, The Pennsylvania State University, 537 ASI Building University Park, PA 16802, USA
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