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Romano PS, Akematsu T, Besteiro S, Bindschedler A, Carruthers VB, Chahine Z, Coppens I, Descoteaux A, Alberto Duque TL, He CY, Heussler V, Le Roch KG, Li FJ, de Menezes JPB, Menna-Barreto RFS, Mottram JC, Schmuckli-Maurer J, Turk B, Tavares Veras PS, Salassa BN, Vanrell MC. Autophagy in protists and their hosts: When, how and why? AUTOPHAGY REPORTS 2023; 2:2149211. [PMID: 37064813 PMCID: PMC10104450 DOI: 10.1080/27694127.2022.2149211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/15/2022] [Indexed: 03/12/2023]
Abstract
Pathogenic protists are a group of organisms responsible for causing a variety of human diseases including malaria, sleeping sickness, Chagas disease, leishmaniasis, and toxoplasmosis, among others. These diseases, which affect more than one billion people globally, mainly the poorest populations, are characterized by severe chronic stages and the lack of effective antiparasitic treatment. Parasitic protists display complex life-cycles and go through different cellular transformations in order to adapt to the different hosts they live in. Autophagy, a highly conserved cellular degradation process, has emerged as a key mechanism required for these differentiation processes, as well as other functions that are crucial to parasite fitness. In contrast to yeasts and mammals, protist autophagy is characterized by a modest number of conserved autophagy-related proteins (ATGs) that, even though, can drive the autophagosome formation and degradation. In addition, during their intracellular cycle, the interaction of these pathogens with the host autophagy system plays a crucial role resulting in a beneficial or harmful effect that is important for the outcome of the infection. In this review, we summarize the current state of knowledge on autophagy and other related mechanisms in pathogenic protists and their hosts. We sought to emphasize when, how, and why this process takes place, and the effects it may have on the parasitic cycle. A better understanding of the significance of autophagy for the protist life-cycle will potentially be helpful to design novel anti-parasitic strategies.
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Affiliation(s)
- Patricia Silvia Romano
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
| | - Takahiko Akematsu
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | | | | | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Zeinab Chahine
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology. Department of Molecular Microbiology and Immunology. Johns Hopkins Malaria Research Institute. Johns Hopkins University Bloomberg School of Public Health. Baltimore 21205, MD, USA
| | - Albert Descoteaux
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique, Laval, QC
| | - Thabata Lopes Alberto Duque
- Autophagy Inflammation and Metabolism Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA; Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Volker Heussler
- Institute of Cell Biology.University of Bern. Baltzerstr. 4 3012 Bern
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Feng-Jun Li
- Department of Biological Sciences, National University of Singapore, Singapore
| | | | | | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | | | - Boris Turk
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Patricia Sampaio Tavares Veras
- Laboratory of Host-Parasite Interaction and Epidemiology, Gonçalo Moniz Institute, Fiocruz-Bahia
- National Institute of Science and Technology of Tropical Diseases - National Council for Scientific Research and Development (CNPq)
| | - Betiana Nebai Salassa
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
| | - María Cristina Vanrell
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
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2
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Goswami P, Samanta SK, Agarwal T, Ghosh SK. Stress-responsive AMP Kinase like protein regulates encystation of Entamoeba invadens. Mol Biochem Parasitol 2022; 251:111507. [PMID: 35870645 DOI: 10.1016/j.molbiopara.2022.111507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 07/16/2022] [Accepted: 07/19/2022] [Indexed: 11/25/2022]
Abstract
Starvation is always accompanied by an increase in the ratio of AMP/ATP followed by activation of AMPK. It is one of the sensors for cellular energy status and is highly conserved across various species. Its role in the stage differentiation process of protozoan species like Giardia, Plasmodium, Trypanosome, and Toxoplasma has been reported. Since Entamoeba undergoes encystation in glucose-starved conditions; it intrigued us to investigate the existence and role of AMPK during the differentiation of trophozoites to the cyst. By employing in silico approaches, we have identified an AMPK homologue which is denominated here as EiAMPK (AMPK-like protein in Entamoeba invadens). Sequence and structural analysis indicate that EiAMPK is sequentially and structurally similar to the AMPK alpha subunit of other organisms. The recombinant form of EiAMPK was functionally active and in accordance, its activity was inhibited by an AMPK-specific inhibitor (eg. Compound C). The increased expression of EiAMPK during different stresses indicated that EiAMPK is a stress-responsive gene. To further investigate, whether EiAMPK has any role in encystation, we employed RNAi-mediated gene silencing that demonstrated its active involvement in encystation. It is known that Entamoeba maintains a flow of glucose from the glycolytic pathway to chitin synthesis for cyst wall formation during encystation. It is conceivable that EiAMPK might have a command over such glucose metabolism. As anticipated, the chitin synthesis was found greatly inhibited in both EiAMPK knockdown and Compound C treated cells, indicating that EiAMPK regulates the cyst wall chitin synthesis.
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Affiliation(s)
- Piyali Goswami
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Sintu Kumar Samanta
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Tarun Agarwal
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Sudip K Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
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Malaria Parasites in a Hungry Host: Kinases and Host Caloric Restriction Brought Together. Trends Parasitol 2017; 33:831-832. [PMID: 28923378 DOI: 10.1016/j.pt.2017.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 08/18/2017] [Indexed: 11/21/2022]
Abstract
A study recently published in Nature links reduced calorie nutritional intake of host mice with (i) reduced severity of cerebral malaria, (ii) decreased parasitemia, and (iii) activation of a nutrient-sensing pathway that regulates the parasite's proliferation rate. Here, we discuss these findings in the context of human malaria pathology and Plasmodium kinomics.
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Moreira D, Silvestre R, Cordeiro-da-Silva A, Estaquier J, Foretz M, Viollet B. AMP-activated Protein Kinase As a Target For Pathogens: Friends Or Foes? Curr Drug Targets 2017; 17:942-53. [PMID: 25882224 DOI: 10.2174/1389450116666150416120559] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 03/24/2015] [Accepted: 04/10/2015] [Indexed: 12/21/2022]
Abstract
Intracellular pathogens are known to manipulate host cell regulatory pathways to establish an optimal environment for their growth and survival. Pathogens employ active mechanisms to hijack host cell metabolism and acquire existing nutrient and energy store. The role of the cellular energy sensor AMP-activated protein kinase (AMPK) in the regulation of cellular energy homeostasis is well documented. Here, we highlight recent advances showing the importance of AMPK signaling in pathogen-host interactions. Pathogens interact with AMPK by a variety of mechanisms aimed at reprogramming host cell metabolism to their own benefit. Stimulation of AMPK activity provides an efficient process to rapidly adapt pathogen metabolism to the major nutritional changes often encountered during the different phases of infection. However, inhibition of AMPK is also used by pathogens to manipulate innate host response, indicating that AMPK appears relevant to restriction of pathogen infection. We also document the effects of pharmacological AMPK modulators on pathogen proliferation and survival. This review illustrates intricate pathogen-AMPK interactions that may be exploited to the development of novel anti-pathogen therapies.
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Affiliation(s)
| | | | | | | | | | - Benoit Viollet
- Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Descartes, 24 rue du faubourg Saint Jacques 75014 Paris, France.
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Mancio-Silva L, Slavic K, Grilo Ruivo MT, Grosso AR, Modrzynska KK, Vera IM, Sales-Dias J, Gomes AR, MacPherson CR, Crozet P, Adamo M, Baena-Gonzalez E, Tewari R, Llinás M, Billker O, Mota MM. Nutrient sensing modulates malaria parasite virulence. Nature 2017; 547:213-216. [PMID: 28678779 PMCID: PMC5511512 DOI: 10.1038/nature23009] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 05/19/2017] [Indexed: 01/06/2023]
Abstract
The lifestyle of intracellular pathogens, such as malaria parasites, is intimately connected to that of their host, primarily for nutrient supply. Nutrients act not only as primary sources of energy but also as regulators of gene expression, metabolism and growth, through various signalling networks that enable cells to sense and adapt to varying environmental conditions. Canonical nutrient-sensing pathways are presumed to be absent from the causative agent of malaria, Plasmodium, thus raising the question of whether these parasites can sense and cope with fluctuations in host nutrient levels. Here we show that Plasmodium blood-stage parasites actively respond to host dietary calorie alterations through rearrangement of their transcriptome accompanied by substantial adjustment of their multiplication rate. A kinome analysis combined with chemical and genetic approaches identified KIN as a critical regulator that mediates sensing of nutrients and controls a transcriptional response to the host nutritional status. KIN shares homology with SNF1/AMPKα, and yeast complementation studies suggest that it is part of a functionally conserved cellular energy-sensing pathway. Overall, these findings reveal a key parasite nutrient-sensing mechanism that is critical for modulating parasite replication and virulence.
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Affiliation(s)
- Liliana Mancio-Silva
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ksenija Slavic
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Margarida T. Grilo Ruivo
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ana Rita Grosso
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | | | - Iset Medina Vera
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Joana Sales-Dias
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ana Rita Gomes
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | | | | | - Mattia Adamo
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Rita Tewari
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, Department of Chemistry, Center for Malaria Research, and Center for Infectious Disease Dynamics, The Pennsylvania State University, State College, Pennsylvania 16802, USA
| | - Oliver Billker
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Maria M. Mota
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
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Phosphorylated and Nonphosphorylated PfMAP2 Are Localized in the Nucleus, Dependent on the Stage of Plasmodium falciparum Asexual Maturation. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1645097. [PMID: 27525262 PMCID: PMC4976173 DOI: 10.1155/2016/1645097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/16/2016] [Indexed: 11/30/2022]
Abstract
Plasmodium falciparum mitogen-activated protein (MAP) kinases, a family of enzymes central to signal transduction processes including inflammatory responses, are a promising target for antimalarial drug development. Our study shows for the first time that the P. falciparum specific MAP kinase 2 (PfMAP2) is colocalized in the nucleus of all of the asexual erythrocytic stages of P. falciparum and is particularly elevated in its phosphorylated form. It was also discovered that PfMAP2 is expressed in its highest quantity during the early trophozoite (ring form) stage and significantly reduced in the mature trophozoite and schizont stages. Although the phosphorylated form of the kinase is always more prevalent, its ratio relative to the nonphosphorylated form remained constant irrespective of the parasites' developmental stage. We have also shown that the TSH motif specifically renders PfMAP2 genetically divergent from the other plasmodial MAP kinase activation sites using Neighbour Joining analysis. Furthermore, TSH motif-specific designed antibody is crucial in determining the location of the expression of the PfMAP2 protein. However, by using immunoelectron microscopy, PPfMAP2 were detected ubiquitously in the parasitized erythrocytes. In summary, PfMAP2 may play a far more important role than previously thought and is a worthy candidate for research as an antimalarial.
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Wu Y, Cruz LN, Szestak T, Laing G, Molyneux GR, Garcia CRS, Craig AG. An external sensing system in Plasmodium falciparum-infected erythrocytes. Malar J 2016; 15:103. [PMID: 26893139 PMCID: PMC4759932 DOI: 10.1186/s12936-016-1144-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/04/2016] [Indexed: 11/17/2022] Open
Abstract
Background A number of experiments have previously indicated that Plasmodium falciparum-infected erythrocytes (pRBC) were able to sense host environment. The basis of this ability to detect external cues is not known but in screening signalling molecules from pRBC using commercial antibodies, a 34 kDa phosphorylated molecule that possesses such ability was identified. Methods The pRBC were exposed to different culture conditions and proteins were extracted for 1D or 2D gel electrophoresis followed by Western blot. The localization of 34 kDa protein was examined by biochemical fractionation followed by Western blot. High-resolution mass spectrometric analysis of immune precipitants was used to identify this protein and real-time quantitative reverse transcriptase polymerase chain reaction was used for detecting mRNA expression level. Results The 34 kDa protein was called PfAB4 has immediate responses (dephosphorylation and rapid turnover) to host environmental stimuli such as serum depletion, osmolality change and cytokine addition. PfAB4 is expressed constitutively throughout the erythrocytic lifecycle with dominant expression in trophozoites 30 h post-infection. Tumour necrosis factor (TNF) treatment induced a transient detectable dephosphorylation of PfAB4 in the ItG strain (2 min after addition) and the level of expression and phosphorylation returned to normal within 1–2 h. PfAB4 localized dominantly in pRBC cytoplasm, with a transient shift to the nucleus under TNF stimulation as shown by biochemical fractionation. High-resolution mass spectrometric analysis of immune precipitants of AB4 antibodies revealed a 34 kDa PfAB4 component as a mixture of proliferating cellular nuclear antigen-1 (PCNA1) and exported protein-2 (EXP2), along with a small number of other inconsistently identified peptides. Different parasite strains have different PfAB4 expression levels, but no significant association between mRNA and PfAB4 levels was seen, indicating that the differences may be at the post-transcriptional, presumably phosphorylation, level. A triple serine phosphorylated PCNA1 peptide was identified from the PfAB4 high expression strain only, providing further evidence that the identity of PfAB4 is PCNA1 in P.falciparum. Conclusion A protein element in the human malaria parasite that responds to external cues, including the pro-inflammatory cytokine TNF have been discovered. Treatment results in a transient change in phosphorylation status of the response element, which also migrates from the parasite cytoplasm to the nucleus. The response element has been identified as PfPCNA1. This sensing response could be regulated by a parasite checkpoint system and be analogous to bacterial two-component signal transduction systems. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1144-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yang Wu
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Laura N Cruz
- Department of Physiology, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
| | - Tadge Szestak
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Gavin Laing
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Gemma R Molyneux
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Celia R S Garcia
- Department of Physiology, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
| | - Alister G Craig
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
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Mesquita I, Moreira D, Sampaio-Marques B, Laforge M, Cordeiro-da-Silva A, Ludovico P, Estaquier J, Silvestre R. AMPK in Pathogens. EXPERIENTIA SUPPLEMENTUM (2012) 2016; 107:287-323. [PMID: 27812985 DOI: 10.1007/978-3-319-43589-3_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
During host-pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host-pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.
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Affiliation(s)
- Inês Mesquita
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | - Diana Moreira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | | | - Anabela Cordeiro-da-Silva
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal
| | - Jérôme Estaquier
- CNRS FR 3636, Université Paris Descartes, Paris, France.,Centre de Recherche du CHU de Québec, Université Laval, Québec, QC, Canada
| | - Ricardo Silvestre
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal. .,ICVS/3Bs-PT Government Associate Laboratory, Guimarães, Braga, Portugal.
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Ward P, Equinet L, Packer J, Doerig C. Protein kinases of the human malaria parasite Plasmodium falciparum: the kinome of a divergent eukaryote. BMC Genomics 2004; 5:79. [PMID: 15479470 PMCID: PMC526369 DOI: 10.1186/1471-2164-5-79] [Citation(s) in RCA: 376] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Accepted: 10/12/2004] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Malaria, caused by the parasitic protist Plasmodium falciparum, represents a major public health problem in the developing world. The P. falciparum genome has been sequenced, which provides new opportunities for the identification of novel drug targets. Eukaryotic protein kinases (ePKs) form a large family of enzymes with crucial roles in most cellular processes; hence malarial ePKS represent potential drug targets. We report an exhaustive analysis of the P. falciparum genomic database (PlasmoDB) aimed at identifying and classifying all ePKs in this organism. RESULTS Using a variety of bioinformatics tools, we identified 65 malarial ePK sequences and constructed a phylogenetic tree to position these sequences relative to the seven established ePK groups. Predominant features of the tree were: (i) that several malarial sequences did not cluster within any of the known ePK groups; (ii) that the CMGC group, whose members are usually involved in the control of cell proliferation, had the highest number of malarial ePKs; and (iii) that no malarial ePK clustered with the tyrosine kinase (TyrK) or STE groups, pointing to the absence of three-component MAPK modules in the parasite. A novel family of 20 ePK-related sequences was identified and called FIKK, on the basis of a conserved amino acid motif. The FIKK family seems restricted to Apicomplexa, with 20 members in P. falciparum and just one member in some other Apicomplexan species. CONCLUSION The considerable phylogenetic distance between Apicomplexa and other Eukaryotes is reflected by profound divergences between the kinome of malaria parasites and that of yeast or mammalian cells.
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Affiliation(s)
- Pauline Ward
- Wellcome Centre for Molecular Parasitology, University of Glasgow, 56 Dumbarton Road, Glasgow G11 6NU, Scotland, UK
| | - Leila Equinet
- INSERM U609, Wellcome Centre for Molecular Parasitology, University of Glasgow, 56 Dumbarton Road, Glasgow G11 6NU, Scotland, UK
| | - Jeremy Packer
- Division of Advanced Technologies, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, USA
| | - Christian Doerig
- INSERM U609, Wellcome Centre for Molecular Parasitology, University of Glasgow, 56 Dumbarton Road, Glasgow G11 6NU, Scotland, UK
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10
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Abstract
Mitochondria of the malaria parasitePlasmodium falciparumare morphologically different between the asexual and sexual blood stages (gametocytes). In this paper recent findings of mitochondrial heterogeneity are reviewed based on their ultrastructural characteristics, metabolic activities and the differential expression of their genes in these 2 blood stages of the parasite. The existence of NADH dehydrogenase (complex I), succinate dehydrogenase (complex II), cytochrome c reductase (complex III) and cytochrome c oxidase (complex IV) suggests that the biochemically active electron transport system operates in this parasite. There is also an alternative electron transport branch pathway, including an anaerobic function of complex II. One of the functional roles of the mitochondrion in the parasite is the coordination of pyrimidine biosynthesis, the electron transport system and oxygen utilization via dihydroorotate dehydrogenase and coenzyme Q. Complete sets of genes encoding enzymes of the tricarboxylic acid cycle and the ATP synthase complex are predicted fromP. falciparumgenomics information. Other metabolic roles of this organelle include membrane potential maintenance, haem and coenzyme Q biosynthesis, and oxidative phosphorylation. Furthermore, the mitochondrion may be a chemotherapeutic target for antimalarial drug development. The antimalarial drug atovaquone targets the mitochondrion.
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Affiliation(s)
- J Krungkrai
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
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11
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Lefebvre DL, Bai Y, Shahmolky N, Sharma M, Poon R, Drucker DJ, Rosen CF. Identification and characterization of a novel sucrose-non-fermenting protein kinase/AMP-activated protein kinase-related protein kinase, SNARK. Biochem J 2001; 355:297-305. [PMID: 11284715 PMCID: PMC1221739 DOI: 10.1042/0264-6021:3550297] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Subtraction hybridization after the exposure of keratinocytes to ultraviolet radiation identified a differentially expressed cDNA that encodes a protein of 630 amino acid residues possessing significant similarity to the catalytic domain of the sucrose-non-fermenting protein kinase (SNF1)/AMP-activated protein kinase (AMPK) family of serine/threonine protein kinases. Northern blotting and reverse-transcriptase-mediated PCR demonstrated that mRNA transcripts for the SNF1/AMPK-related kinase (SNARK) were widely expressed in rodent tissues. The SNARK gene was localized to human chromosome 1q32 by fluorescent in situ hybridization. SNARK was translated in vitro to yield a single protein band of approx. 76 kDa; Western analysis of transfected baby hamster kidney (BHK) cells detected two SNARK-immunoreactive bands of approx. 76-80 kDa. SNARK was capable of autophosphorylation in vitro; immunoprecipitated SNARK exhibited phosphotransferase activity with the synthetic peptide substrate HMRSAMSGLHLVKRR (SAMS) as a kinase substrate. SNARK activity was significantly increased by AMP and 5-amino-4-imidazolecarboxamide riboside (AICAriboside) in rat keratinocyte cells, implying that SNARK might be activated by an AMPK kinase-dependent pathway. Furthermore, glucose deprivation increased SNARK activity 3-fold in BHK fibroblasts. These findings identify SNARK as a glucose- and AICAriboside-regulated member of the AMPK-related gene family that represents a new candidate mediator of the cellular response to metabolic stress.
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Affiliation(s)
- D L Lefebvre
- Department of Medicine, Division of Dermatology, Toronto General Hospital, Banting Institute, Room 317, 100 College Street, Toronto M5G 1L5, Ontario, Canada
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Kappes B, Doerig CD, Graeser R. An overview of Plasmodium protein kinases. PARASITOLOGY TODAY (PERSONAL ED.) 1999; 15:449-54. [PMID: 10511687 DOI: 10.1016/s0169-4758(99)01527-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protein kinases are key regulators of many biochemical processes in eukaryotic cells. Malaria parasites, in spite of all their peculiarities, are not likely to represent an exception in this respect. Over the past few years, several genes encoding Plasmodium protein kinases have been cloned and characterized; these molecular studies extend previous data on kinase activities in parasite extracts. Here, Barbara Kappes, Christian Doerig and Ralph Graeser present available data on this topic, with an emphasis on cloned protein kinase genes, and discuss the potential outcome of such research in the context of drug development.
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Affiliation(s)
- B Kappes
- Center of Biochemistry, Heidelberg University, Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany.
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Learngaramkul P, Petmitr S, Krungkrai SR, Prapunwattana P, Krungkrai J. Molecular characterization of mitochondria in asexual and sexual blood stages of Plasmodium falciparum. MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 1999; 2:15-20. [PMID: 10527885 DOI: 10.1006/mcbr.1999.0145] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular mechanisms that regulate gene expression during development of asexual stage to sexual stage of Plasmodium falciparum in the human erythrocyte are largely unknown. There were apparent variations in ultrastructural characteristics of the mitochondrion between the two developing stages. The asexual stage's mitochondrion had developed less than that of the sexual stage. The respiratory complexes of the mitochondrial electron transport system in the asexual stage were approximately 8-10 times less active than those in the sexual stage. Using quantitative polymerase chain reaction to amplify the cytochrome b gene encoding a subunit of mitochondrial cytochrome c reductase, the amount of the cytochrome b gene of the sexual stage was calculated to be approximately 3 times higher than that obtained from the asexual stage. Moreover, using quantitative reverse-transcription polymerase chain reaction, a relatively high level of approximately 1.3-kb transcript mRNA of the cytochrome b gene was observed in the sexual stage compared to the asexual stage. A known single-copy chromosomal dihydrofolate reductase gene was found to have a similar amount in the two stages. These results suggest that the copy number of the mitochondrial gene, including transcriptional and translational mechanisms, plays a major regulatory role in differential expression during the development of the asexual to sexual stage of P. falciparum in the human cell.
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Affiliation(s)
- P Learngaramkul
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Li JL, Baker DA. Protein phosphatase beta, a putative type-2A protein phosphatase from the human malaria parasite Plasmodium falciparum. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 249:98-106. [PMID: 9363759 DOI: 10.1111/j.1432-1033.1997.t01-2-00098.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Protein phosphatases play a critical role in the regulation of the eukaryotic cell cycle and signal transduction. A putative protein serine/threonine phosphatase gene has been isolated from the human malaria parasite Plasmodium falciparum. The gene has an unusual intron that contains four repeats of 32 nucleotides and displays a high degree of size polymorphism among different strains of P. falciparum. The open reading frame reconstituted by removal of the intron encodes a protein of 466 amino acids with a predicted molecular mass of approximately 53.7 kDa. The encoded protein, termed protein phosphatase beta (PP-beta), is composed of two distinct domains. The C-terminal domain comprises 315 amino acids and exhibits a striking similarity to the catalytic subunits of the type-2A protein phosphatases. Database searches revealed that the catalytic domain has the highest similarity to Schizosaccharomyces pombe Ppa1 (58% identity and 73% similarity). However, it contains a hydrophilic insert consisting of five amino acids. The N-terminal domain comprises 151 amino acid residues and exhibits several striking features, including high levels of charged amino acids and asparagine, and multiple consensus phosphorylation sites for a number of protein kinases. An overall structural comparison of PP-beta with other members of the protein phosphatase 2A group revealed that PP-beta is more closely related to Saccharomyces cerevisiae PPH22. Southern blots of genomic DNA digests and chromosomal separations showed that PP-beta is a single-copy gene and is located on chromosome 9. A 2800-nucleotide transcript of this gene is expressed specifically in the sexual erythrocytic stage (gametocytes). The results indicate that PP-beta may be involved in sexual stage development.
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Affiliation(s)
- J L Li
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
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Abstract
Over the past few years, several reports have been published about the characterization of Plasmodium genes that are thought, on the basis of sequence homology with eukaryotic genes of known function, to be involved in the regulation of growth and differentiation of the parasite. Taken together with phenomenological observations on the regulation of developmental stages in the malaria life cycle, these data form the basis of an informative, albeit incomplete, picture of signal transtruction in Plasmodium. Christian Doerig here reviews Plasmodium elements that are presumably part of major regulatory pathways conserved in eukaryotes, and addresses the problem of how to pursue such studies beyond the stage of gene identification.
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Affiliation(s)
- C D Doerig
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 313. Centre Hospitalier Universitaire Pitié-Salpêtrière, 91 Boulevard de l'Hôpital, 75013 Paris, France
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