1
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Schlott AC, Knuepfer E, Green JL, Hobson P, Borg AJ, Morales-Sanfrutos J, Perrin AJ, Maclachlan C, Collinson LM, Snijders AP, Tate EW, Holder AA. Inhibition of protein N-myristoylation blocks Plasmodium falciparum intraerythrocytic development, egress and invasion. PLoS Biol 2021; 19:e3001408. [PMID: 34695132 PMCID: PMC8544853 DOI: 10.1371/journal.pbio.3001408] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/07/2021] [Indexed: 11/29/2022] Open
Abstract
We have combined chemical biology and genetic modification approaches to investigate the importance of protein myristoylation in the human malaria parasite, Plasmodium falciparum. Parasite treatment during schizogony in the last 10 to 15 hours of the erythrocytic cycle with IMP-1002, an inhibitor of N-myristoyl transferase (NMT), led to a significant blockade in parasite egress from the infected erythrocyte. Two rhoptry proteins were mislocalized in the cell, suggesting that rhoptry function is disrupted. We identified 16 NMT substrates for which myristoylation was significantly reduced by NMT inhibitor (NMTi) treatment, and, of these, 6 proteins were substantially reduced in abundance. In a viability screen, we showed that for 4 of these proteins replacement of the N-terminal glycine with alanine to prevent myristoylation had a substantial effect on parasite fitness. In detailed studies of one NMT substrate, glideosome-associated protein 45 (GAP45), loss of myristoylation had no impact on protein location or glideosome assembly, in contrast to the disruption caused by GAP45 gene deletion, but GAP45 myristoylation was essential for erythrocyte invasion. Therefore, there are at least 3 mechanisms by which inhibition of NMT can disrupt parasite development and growth: early in parasite development, leading to the inhibition of schizogony and formation of “pseudoschizonts,” which has been described previously; at the end of schizogony, with disruption of rhoptry formation, merozoite development and egress from the infected erythrocyte; and at invasion, when impairment of motor complex function prevents invasion of new erythrocytes. These results underline the importance of P. falciparum NMT as a drug target because of the pleiotropic effect of its inhibition. Understanding the essential factors needed for malaria parasite development could help us find new therapeutic targets. This study reveals that N-myristoylation is a posttranslational modification of proteins essential for the parasites’ growth and their invasion of red blood cells.
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Affiliation(s)
- Anja C. Schlott
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
- Molecular Sciences Research Hub, Imperial College, London, United Kingdom
| | - Ellen Knuepfer
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hatfield, United Kingdom
| | - Judith L. Green
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
| | - Philip Hobson
- Flow Cytometry Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Aaron J. Borg
- Mass Spectrometry Proteomics Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | | | - Abigail J. Perrin
- Malaria Biochemistry Laboratory, Francis Crick Institute, London, United Kingdom
| | - Catherine Maclachlan
- Electron Microscopy Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Lucy M. Collinson
- Electron Microscopy Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Ambrosius P. Snijders
- Mass Spectrometry Proteomics Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Edward W. Tate
- Molecular Sciences Research Hub, Imperial College, London, United Kingdom
- Francis Crick Institute, London, United Kingdom
- * E-mail: (EWT); (AAH)
| | - Anthony A. Holder
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
- * E-mail: (EWT); (AAH)
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2
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Perrin AJ, Bisson C, Faull PA, Renshaw MJ, Lees RA, Fleck RA, Saibil HR, Snijders AP, Baker DA, Blackman MJ. Malaria Parasite Schizont Egress Antigen-1 Plays an Essential Role in Nuclear Segregation during Schizogony. mBio 2021; 12:e03377-20. [PMID: 33688001 PMCID: PMC8092294 DOI: 10.1128/mbio.03377-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/25/2021] [Indexed: 01/08/2023] Open
Abstract
Malaria parasites cause disease through repeated cycles of intraerythrocytic proliferation. Within each cycle, several rounds of DNA replication produce multinucleated forms, called schizonts, that undergo segmentation to form daughter merozoites. Upon rupture of the infected cell, the merozoites egress to invade new erythrocytes and repeat the cycle. In human malarial infections, an antibody response specific for the Plasmodium falciparum protein PF3D7_1021800 was previously associated with protection against malaria, leading to an interest in PF3D7_1021800 as a candidate vaccine antigen. Antibodies to the protein were reported to inhibit egress, resulting in it being named schizont egress antigen-1 (SEA1). A separate study found that SEA1 undergoes phosphorylation in a manner dependent upon the parasite cGMP-dependent protein kinase PKG, which triggers egress. While these findings imply a role for SEA1 in merozoite egress, this protein has also been implicated in kinetochore function during schizont development. Therefore, the function of SEA1 remains unclear. Here, we show that P. falciparum SEA1 localizes in proximity to centromeres within dividing nuclei and that conditional disruption of SEA1 expression severely impacts the distribution of DNA and formation of merozoites during schizont development, with a proportion of SEA1-null merozoites completely lacking nuclei. SEA1-null schizonts rupture, albeit with low efficiency, suggesting that neither SEA1 function nor normal segmentation is a prerequisite for egress. We conclude that SEA1 does not play a direct mechanistic role in egress but instead acts upstream of egress as an essential regulator required to ensure the correct packaging of nuclei within merozoites.IMPORTANCE Malaria is a deadly infectious disease. Rationally designed novel therapeutics will be essential for its control and eradication. The Plasmodium falciparum protein PF3D7_1021800, annotated as SEA1, is under investigation as a prospective component of a malaria vaccine, based on previous indications that antibodies to SEA1 interfere with parasite egress from infected erythrocytes. However, a consensus on the function of SEA1 is lacking. Here, we demonstrate that SEA1 localizes to dividing parasite nuclei and is necessary for the correct segregation of replicated DNA into individual daughter merozoites. In the absence of SEA1, merozoites develop defectively, often completely lacking a nucleus, and, consequently, egress is impaired and/or aberrant. Our findings provide insights into the divergent mechanisms by which intraerythrocytic malaria parasites develop and divide. Our conclusions regarding the localization and function of SEA1 are not consistent with the hypothesis that antibodies against it confer protective immunity to malaria by blocking merozoite egress.
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Affiliation(s)
- Abigail J Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Claudine Bisson
- Department of Biological Sciences, Institute of Structural & Molecular Biology, Birkbeck College, University of London, London, United Kingdom
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, United Kingdom
| | - Peter A Faull
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, United Kingdom
| | - Matthew J Renshaw
- Advanced Light Microscopy, The Francis Crick Institute, London, United Kingdom
| | - Rebecca A Lees
- Department of Biological Sciences, Institute of Structural & Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Roland A Fleck
- Centre for Ultrastructural Imaging, Guy's Campus, King's College London, London, United Kingdom
| | - Helen R Saibil
- Department of Biological Sciences, Institute of Structural & Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Ambrosius P Snijders
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, United Kingdom
| | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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3
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Balestra AC, Koussis K, Klages N, Howell SA, Flynn HR, Bantscheff M, Pasquarello C, Perrin AJ, Brusini L, Arboit P, Sanz O, Castaño LPB, Withers-Martinez C, Hainard A, Ghidelli-Disse S, Snijders AP, Baker DA, Blackman MJ, Brochet M. Ca 2+ signals critical for egress and gametogenesis in malaria parasites depend on a multipass membrane protein that interacts with PKG. Sci Adv 2021; 7:7/13/eabe5396. [PMID: 33762339 PMCID: PMC7990342 DOI: 10.1126/sciadv.abe5396] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Calcium signaling regulated by the cGMP-dependent protein kinase (PKG) controls key life cycle transitions in the malaria parasite. However, how calcium is mobilized from intracellular stores in the absence of canonical calcium channels in Plasmodium is unknown. Here, we identify a multipass membrane protein, ICM1, with homology to transporters and calcium channels that is tightly associated with PKG in both asexual blood stages and transmission stages. Phosphoproteomic analyses reveal multiple ICM1 phosphorylation events dependent on PKG activity. Stage-specific depletion of Plasmodium berghei ICM1 prevents gametogenesis due to a block in intracellular calcium mobilization, while conditional loss of Plasmodium falciparum ICM1 is detrimental for the parasite resulting in severely reduced calcium mobilization, defective egress, and lack of invasion. Our findings suggest that ICM1 is a key missing link in transducing PKG-dependent signals and provide previously unknown insights into atypical calcium homeostasis in malaria parasites essential for pathology and disease transmission.
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Affiliation(s)
- Aurélia C Balestra
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Konstantinos Koussis
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | - Natacha Klages
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Steven A Howell
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, UK
| | - Helen R Flynn
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, UK
| | - Marcus Bantscheff
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, 69117 Heidelberg, Germany
| | - Carla Pasquarello
- Proteomics Core Facility, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Abigail J Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK
| | - Lorenzo Brusini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Patrizia Arboit
- Proteomics Core Facility, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Olalla Sanz
- Diseases of the Developing World Global Health Pharma Unit, GlaxoSmithKline, 28760 Tres Cantos, Spain
| | | | | | - Alexandre Hainard
- Proteomics Core Facility, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Sonja Ghidelli-Disse
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline, 69117 Heidelberg, Germany
| | | | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland.
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Perrin AJ, Patel A, Flueck C, Blackman MJ, Baker DA. cAMP signalling and its role in host cell invasion by malaria parasites. Curr Opin Microbiol 2020; 58:69-74. [PMID: 33032143 DOI: 10.1016/j.mib.2020.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) is an important signalling molecule across evolution, but until recently there was little information on its role in malaria parasites. Advances in gene editing - in particular conditional genetic approaches and mass spectrometry have paved the way for characterisation of the key components of the cAMP signalling pathway in malaria parasites. This has revealed that cAMP signalling plays a critical role in invasion of host red blood cells by Plasmodium falciparum merozoites through regulating the phosphorylation of key parasite proteins by the cAMP-dependent protein kinase (PKA). These insights will help us to investigate parasite cAMP signalling as a target for novel antimalarial drugs.
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Affiliation(s)
- Abigail J Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Avnish Patel
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christian Flueck
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David A Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom.
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5
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Sherling ES, Perrin AJ, Knuepfer E, Russell MRG, Collinson LM, Miller LH, Blackman MJ. The Plasmodium falciparum rhoptry bulb protein RAMA plays an essential role in rhoptry neck morphogenesis and host red blood cell invasion. PLoS Pathog 2019; 15:e1008049. [PMID: 31491036 PMCID: PMC6750612 DOI: 10.1371/journal.ppat.1008049] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 09/18/2019] [Accepted: 08/27/2019] [Indexed: 01/08/2023] Open
Abstract
The malaria parasite Plasmodium falciparum invades, replicates within and destroys red blood cells in an asexual blood stage life cycle that is responsible for clinical disease and crucial for parasite propagation. Invasive malaria merozoites possess a characteristic apical complex of secretory organelles that are discharged in a tightly controlled and highly regulated order during merozoite egress and host cell invasion. The most prominent of these organelles, the rhoptries, are twinned, club-shaped structures with a body or bulb region that tapers to a narrow neck as it meets the apical prominence of the merozoite. Different protein populations localise to the rhoptry bulb and neck, but the function of many of these proteins and how they are spatially segregated within the rhoptries is unknown. Using conditional disruption of the gene encoding the only known glycolipid-anchored malarial rhoptry bulb protein, rhoptry-associated membrane antigen (RAMA), we demonstrate that RAMA is indispensable for blood stage parasite survival. Contrary to previous suggestions, RAMA is not required for trafficking of all rhoptry bulb proteins. Instead, RAMA-null parasites display selective mislocalisation of a subset of rhoptry bulb and neck proteins (RONs) and produce dysmorphic rhoptries that lack a distinct neck region. The mutant parasites undergo normal intracellular development and egress but display a fatal defect in invasion and do not induce echinocytosis in target red blood cells. Our results indicate that distinct pathways regulate biogenesis of the two main rhoptry sub-compartments in the malaria parasite. Despite improved control measures over recent decades, malaria is still a considerable health burden across much of the globe. The disease is caused by a single-celled parasite that invades and replicates within host cells. During invasion, the parasite discharges a set of flask-shaped secretory organelles called rhoptries, the contents of which are crucial for invasion as well as for modifications to the host cell that are important for parasite survival. Rhoptry discharge occurs through fusion of the relatively elongated rhoptry neck to the apical surface of the parasite. Different proteins reside within the bulbous rhoptry body and the neck regions, but how these proteins are selectively sent to their correct sub-compartments within the rhoptries and how the rhoptries are formed, is poorly understood. Here we show that a malaria parasite rhoptry bulb protein called rhoptry-associated membrane antigen (RAMA) plays an essential role in rhoptry neck formation and correct trafficking of certain rhoptry neck and bulb proteins. Parasites deficient in RAMA produce malformed rhoptries and–probably as a result—cannot invade host red blood cells. Our work sheds new light on how rhoptries are formed and reveals insights into the mechanism by which the correct sorting of proteins to distinct regions of the rhoptry is regulated.
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Affiliation(s)
- Emma S. Sherling
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Abigail J. Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Ellen Knuepfer
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Matthew R. G. Russell
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Lucy M. Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Louis H. Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Michael J. Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
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6
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Patel A, Perrin AJ, Flynn HR, Bisson C, Withers-Martinez C, Treeck M, Flueck C, Nicastro G, Martin SR, Ramos A, Gilberger TW, Snijders AP, Blackman MJ, Baker DA. Cyclic AMP signalling controls key components of malaria parasite host cell invasion machinery. PLoS Biol 2019; 17:e3000264. [PMID: 31075098 PMCID: PMC6530879 DOI: 10.1371/journal.pbio.3000264] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 05/22/2019] [Accepted: 04/26/2019] [Indexed: 01/01/2023] Open
Abstract
Cyclic AMP (cAMP) is an important signalling molecule across evolution, but its role in malaria parasites is poorly understood. We have investigated the role of cAMP in asexual blood stage development of Plasmodium falciparum through conditional disruption of adenylyl cyclase beta (ACβ) and its downstream effector, cAMP-dependent protein kinase (PKA). We show that both production of cAMP and activity of PKA are critical for erythrocyte invasion, whilst key developmental steps that precede invasion still take place in the absence of cAMP-dependent signalling. We also show that another parasite protein with putative cyclic nucleotide binding sites, Plasmodium falciparum EPAC (PfEpac), does not play an essential role in blood stages. We identify and quantify numerous sites, phosphorylation of which is dependent on cAMP signalling, and we provide mechanistic insight as to how cAMP-dependent phosphorylation of the cytoplasmic domain of the essential invasion adhesin apical membrane antigen 1 (AMA1) regulates erythrocyte invasion.
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Affiliation(s)
- Avnish Patel
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Abigail J. Perrin
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Helen R. Flynn
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, United Kingdom
| | - Claudine Bisson
- Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom
| | | | - Moritz Treeck
- Signalling in Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Christian Flueck
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Giuseppe Nicastro
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Stephen R. Martin
- Macromolecular Structure Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Andres Ramos
- Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Tim W. Gilberger
- Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ambrosius P. Snijders
- Mass Spectrometry Proteomics Platform, The Francis Crick Institute, London, United Kingdom
| | - Michael J. Blackman
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - David A. Baker
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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7
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Flueck C, Drought LG, Jones A, Patel A, Perrin AJ, Walker EM, Nofal SD, Snijders AP, Blackman MJ, Baker DA. Phosphodiesterase beta is the master regulator of cAMP signalling during malaria parasite invasion. PLoS Biol 2019; 17:e3000154. [PMID: 30794532 PMCID: PMC6402698 DOI: 10.1371/journal.pbio.3000154] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 03/06/2019] [Accepted: 02/05/2019] [Indexed: 12/29/2022] Open
Abstract
Cyclic nucleotide signalling is a major regulator of malaria parasite differentiation. Phosphodiesterase (PDE) enzymes are known to control cyclic GMP (cGMP) levels in the parasite, but the mechanisms by which cyclic AMP (cAMP) is regulated remain enigmatic. Here, we demonstrate that Plasmodium falciparum phosphodiesterase β (PDEβ) hydrolyses both cAMP and cGMP and is essential for blood stage viability. Conditional gene disruption causes a profound reduction in invasion of erythrocytes and rapid death of those merozoites that invade. We show that this dual phenotype results from elevated cAMP levels and hyperactivation of the cAMP-dependent protein kinase (PKA). Phosphoproteomic analysis of PDEβ-null parasites reveals a >2-fold increase in phosphorylation at over 200 phosphosites, more than half of which conform to a PKA substrate consensus sequence. We conclude that PDEβ plays a critical role in governing correct temporal activation of PKA required for erythrocyte invasion, whilst suppressing untimely PKA activation during early intra-erythrocytic development.
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Affiliation(s)
- Christian Flueck
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Laura G. Drought
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Andrew Jones
- Protein Analysis and Proteomics Laboratory, the Francis Crick Institute, London, United Kingdom
| | - Avnish Patel
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Abigail J. Perrin
- Malaria Biochemistry Laboratory, the Francis Crick Institute, London, United Kingdom
| | - Eloise M. Walker
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Stephanie D. Nofal
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ambrosius P. Snijders
- Protein Analysis and Proteomics Laboratory, the Francis Crick Institute, London, United Kingdom
| | - Michael J. Blackman
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Malaria Biochemistry Laboratory, the Francis Crick Institute, London, United Kingdom
| | - David A. Baker
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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8
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Das S, Hertrich N, Perrin AJ, Withers-Martinez C, Collins CR, Jones ML, Watermeyer JM, Fobes ET, Martin SR, Saibil HR, Wright GJ, Treeck M, Epp C, Blackman MJ. Processing of Plasmodium falciparum Merozoite Surface Protein MSP1 Activates a Spectrin-Binding Function Enabling Parasite Egress from RBCs. Cell Host Microbe 2016; 18:433-44. [PMID: 26468747 PMCID: PMC4608996 DOI: 10.1016/j.chom.2015.09.007] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/17/2015] [Accepted: 09/18/2015] [Indexed: 11/09/2022]
Abstract
The malaria parasite Plasmodium falciparum replicates within erythrocytes, producing progeny merozoites that are released from infected cells via a poorly understood process called egress. The most abundant merozoite surface protein, MSP1, is synthesized as a large precursor that undergoes proteolytic maturation by the parasite protease SUB1 just prior to egress. The function of MSP1 and its processing are unknown. Here we show that SUB1-mediated processing of MSP1 is important for parasite viability. Processing modifies the secondary structure of MSP1 and activates its capacity to bind spectrin, a molecular scaffold protein that is the major component of the host erythrocyte cytoskeleton. Parasites expressing an inefficiently processed MSP1 mutant show delayed egress, and merozoites lacking surface-bound MSP1 display a severe egress defect. Our results indicate that interactions between SUB1-processed merozoite surface MSP1 and the spectrin network of the erythrocyte cytoskeleton facilitate host erythrocyte rupture to enable parasite egress. Merozoite surface protein MSP1 processing is important for P. falciparum viability Proteolytic processing activates MSP1’s heparin and spectrin-binding functions The rate of MSP1 processing governs the kinetics of parasite egress Loss of parasite surface MSP1 results in a severe egress defect
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Affiliation(s)
- Sujaan Das
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, NW7 1AA, UK
| | - Nadine Hertrich
- Department für Infektiologie, Parasitologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
| | - Abigail J Perrin
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1HH, UK
| | | | - Christine R Collins
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, NW7 1AA, UK
| | - Matthew L Jones
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, NW7 1AA, UK
| | - Jean M Watermeyer
- Department of Crystallography, Birkbeck College, London, WC1E 7HX, UK
| | - Elmar T Fobes
- Department für Infektiologie, Parasitologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
| | - Stephen R Martin
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, NW7 1AA, UK
| | - Helen R Saibil
- Department of Crystallography, Birkbeck College, London, WC1E 7HX, UK
| | - Gavin J Wright
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1HH, UK
| | - Moritz Treeck
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, NW7 1AA, UK
| | - Christian Epp
- Department für Infektiologie, Parasitologie, Universitätsklinikum Heidelberg, D-69120 Heidelberg, Germany
| | - Michael J Blackman
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, NW7 1AA, UK; Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
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9
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Crosnier C, Iqbal Z, Knuepfer E, Maciuca S, Perrin AJ, Kamuyu G, Goulding D, Bustamante LY, Miles A, Moore SC, Dougan G, Holder AA, Kwiatkowski DP, Rayner JC, Pleass RJ, Wright GJ. Binding of Plasmodium falciparum Merozoite Surface Proteins DBLMSP and DBLMSP2 to Human Immunoglobulin M Is Conserved among Broadly Diverged Sequence Variants. J Biol Chem 2016; 291:14285-14299. [PMID: 27226583 PMCID: PMC4933183 DOI: 10.1074/jbc.m116.722074] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 11/17/2022] Open
Abstract
Diversity at pathogen genetic loci can be driven by host adaptive immune selection pressure and may reveal proteins important for parasite biology. Population-based genome sequencing of Plasmodium falciparum, the parasite responsible for the most severe form of malaria, has highlighted two related polymorphic genes called dblmsp and dblmsp2, which encode Duffy binding-like (DBL) domain-containing proteins located on the merozoite surface but whose function remains unknown. Using recombinant proteins and transgenic parasites, we show that DBLMSP and DBLMSP2 directly and avidly bind human IgM via their DBL domains. We used whole genome sequence data from over 400 African and Asian P. falciparum isolates to show that dblmsp and dblmsp2 exhibit extreme protein polymorphism in their DBL domain, with multiple variants of two major allelic classes present in every population tested. Despite this variability, the IgM binding function was retained across diverse sequence representatives. Although this interaction did not seem to have an effect on the ability of the parasite to invade red blood cells, binding of DBLMSP and DBLMSP2 to IgM inhibited the overall immunoreactivity of these proteins to IgG from patients who had been exposed to the parasite. This suggests that IgM binding might mask these proteins from the host humoral immune system.
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Affiliation(s)
- Cécile Crosnier
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Zamin Iqbal
- Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Ellen Knuepfer
- Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Sorina Maciuca
- Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Abigail J Perrin
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Gathoni Kamuyu
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - David Goulding
- Microbial Pathogenesis Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Leyla Y Bustamante
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Alistair Miles
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Shona C Moore
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom; Warwick Systems Biology Centre, Senate House, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Gordon Dougan
- Microbial Pathogenesis Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Anthony A Holder
- Francis Crick Institute, Mill Hill Laboratory, London NW7 1AA, United Kingdom
| | - Dominic P Kwiatkowski
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, United Kingdom
| | - Julian C Rayner
- Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Richard J Pleass
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Gavin J Wright
- Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom; Malaria Programme, Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom.
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Abstract
BACKGROUND Plasmodium parasites typically elicit a non-sterile but protective immune response in human host populations, suggesting that the parasites actively modulate normal immunological mechanisms. P-selectin is a cell surface receptor expressed in mammals, that is a known component of the inflammatory response against pathogens and has been previously identified as a host factor that influences malaria-associated pathology both in human patients and rodent infection models. METHODS To better understand the molecular mechanisms underlying the involvement of P-selectin in the pathogenesis of malaria, a systematic extracellular protein interaction screen was used to identify Plasmodium falciparum merozoite surface protein 7 (MSP7) as a binding partner of human P-selectin. This interaction, and those occurring between P-selectin and Plasmodium MSP7 homologues, was characterized biochemically. RESULTS Plasmodium falciparum MSP7 and P-selectin were shown to bind each other directly via the N-terminus of PfMSP7 and the P-selectin C-type lectin and EGF-like domains. Orthologous proteins in the murine parasite Plasmodium berghei (PbMSRP1 and PbMSRP2) and mouse P-selectin also interacted. Finally, P-selectin, when complexed with MSP7, could no longer bind to its endogenous carbohydrate ligand, Sialyl-Lewis(X). CONCLUSIONS Novel interactions were identified between Plasmodium MSP7 protein family members and host P-selectin receptors. Since PfMSP7 could prevent interactions between P-selectin and its leukocyte ligands, these results provide a possible mechanism for the known immunomodulatory effects of both MSP7 and P-selectin in malaria infection models.
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Affiliation(s)
- Abigail J Perrin
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
| | - S Josefin Bartholdson
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
| | - Gavin J Wright
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
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Saetear P, Perrin AJ, Bartholdson SJ, Wanaguru M, Kussrow A, Bornhop DJ, Wright GJ. Quantification of Plasmodium-host protein interactions on intact, unmodified erythrocytes by back-scattering interferometry. Malar J 2015; 14:88. [PMID: 25889240 PMCID: PMC4349660 DOI: 10.1186/s12936-015-0553-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 01/06/2015] [Indexed: 11/17/2022] Open
Abstract
Background Invasion of host erythrocytes by Plasmodium falciparum is central to the pathogenesis of malaria. Invasion involves recognition events between erythrocyte receptors and ligands on the merozoite, the invasive blood form of the parasite. Identifying and characterizing host-parasite interactions is impeded by the biochemical challenges of working with membrane-embedded glycoprotein receptors. For example, the interaction between P. falciparum erythrocyte binding antigen 175 (PfEBA175) and glycophorin A (GYPA) depends on post-translational modifications that are not easily added in recombinant expression systems, and the use of native GYPA is limited by the hydrophobic transmembrane region, making it difficult to biochemically manipulate. It would, therefore, be desirable to perform quantitative binding assays with receptors embedded within the membranes of intact human erythrocytes. Methods The extracellular region of GYPA was over-expressed as a soluble protein in HEK293E cells. This protein was characterized, sialylated and evaluated for binding to the PfEBA175 protein. The label-free and free-solution assay, backscattering interferometry (BSI), was used to perform binding assays of two well-characterized P. falciparum invasion ligands to intact unmodified human erythrocytes. Results Findings indicate that the post-translational modifications present on native GYPA are required for it to bind recombinant PfEBA175 and that these modifications cannot be recapitulated in vitro using mammalian overexpression methods. Here, BSI was used to obtain quantitative, high fidelity interaction determinations on intact, unmodified erythrocytes. Using BSI and purified recombinant proteins constituting the entire ectodomains of the P. falciparum merozoite ligands PfEBA175 and PfRH5, KDs of 1.1 μM and 50 nM were measured for the PfRH5-BSG and PfEBA175-GYPA interactions, respectively, in good agreement with previous biophysical measurements of these interactions. Conclusions These results demonstrate that BSI can be used to detect and quantify the interactions of two merozoite invasion ligands with their receptors on intact human erythrocytes. BSI assays were performed on unlabelled, free-solution proteins in their native environment, requiring only nanomoles of recombinant protein. This study suggests that BSI can be used to investigate host-parasite protein interactions without the limitations of other assay platforms, and therefore represents a valuable new method to investigate the molecular mechanisms involved in erythrocyte invasion by P. falciparum.
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Affiliation(s)
- Phoonthawee Saetear
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
| | - Abigail J Perrin
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
| | - S Josefin Bartholdson
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
| | - Madushi Wanaguru
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
| | - Amanda Kussrow
- Department of Chemistry and the Vanderbilt Institute for Chemical Biology, Vanderbilt University, 4226 Stevenson Center, Nashville, Tennessee, 37235, USA.
| | - Darryl J Bornhop
- Department of Chemistry and the Vanderbilt Institute for Chemical Biology, Vanderbilt University, 4226 Stevenson Center, Nashville, Tennessee, 37235, USA.
| | - Gavin J Wright
- Cell Surface Signalling Laboratory and Malaria Programme, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK.
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Perrin AJ, Gunda M, Yu B, Yen K, Ito S, Forster S, Tissenbaum HA, Derry WB. Noncanonical control of C. elegans germline apoptosis by the insulin/IGF-1 and Ras/MAPK signaling pathways. Cell Death Differ 2012; 20:97-107. [PMID: 22935616 DOI: 10.1038/cdd.2012.101] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The insulin/IGF-1 pathway controls a number of physiological processes in the nematode worm Caenorhabditis elegans, including development, aging and stress response. We previously found that the Akt/PKB ortholog AKT-1 dampens the apoptotic response to genotoxic stress in the germline by negatively regulating the p53-like transcription factor CEP-1. Here, we report unexpected rearrangements to the insulin/IGF-1 pathway, whereby the insulin-like receptor DAF-2 and 3-phosphoinositide-dependent protein kinase PDK-1 oppose AKT-1 to promote DNA damage-induced apoptosis. While DNA damage does not affect phosphorylation at the PDK-1 site Thr350/Thr308 of AKT-1, it increased phosphorylation at Ser517/Ser473. Although ablation of daf-2 or pdk-1 completely suppressed akt-1-dependent apoptosis, the transcriptional activation of CEP-1 was unaffected, suggesting that daf-2 and pdk-1 act independently or downstream of cep-1 and akt-1. Ablation of the akt-1 paralog akt-2 or the downstream target of the insulin/IGF-1 pathway daf-16 (a FOXO transcription factor) restored sensitivity to damage-induced apoptosis in daf-2 and pdk-1 mutants. In addition, daf-2 and pdk-1 mutants have reduced levels of phospho-MPK-1/ERK in their germ cells, indicating that the insulin/IGF-1 pathway promotes Ras signaling in the germline. Ablation of the Ras effector gla-3, a negative regulator of mpk-1, restored sensitivity to apoptosis in daf-2 mutants, suggesting that gla-3 acts downstream of daf-2. In addition, the hypersensitivity of let-60/Ras gain-of-function mutants to damage-induced apoptosis was suppressed to wild-type levels by ablation of daf-2. Thus, insulin/IGF-1 signaling selectively engages AKT-2/DAF-16 to promote DNA damage-induced germ cell apoptosis downstream of CEP-1 through the Ras pathway.
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Affiliation(s)
- A J Perrin
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
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Abstract
Salmonella occupies a vacuolar compartment inside cells of its host. Recent studies have shown that the fate of this vacuole is different in various cell types, and that the outcome of colonization is determined by both the infecting bacterium and defense mechanisms of the host cell.
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Affiliation(s)
- J H Brumell
- Biotechnology Laboratory and Department of Microbiology and Immunology, University of British Columbia, British Columbia, V6T-1Z3, Vancouver, Canada
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