1
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Ling DB, Nguyen W, Looker O, Razook Z, McCann K, Barry AE, Scheurer C, Wittlin S, Famodimu MT, Delves MJ, Bullen HE, Crabb BS, Sleebs BE, Gilson PR. A Pyridyl-Furan Series Developed from the Open Global Health Library Block Red Blood Cell Invasion and Protein Trafficking in Plasmodium falciparum through Potential Inhibition of the Parasite's PI4KIIIB Enzyme. ACS Infect Dis 2023; 9:1695-1710. [PMID: 37639221 PMCID: PMC10496428 DOI: 10.1021/acsinfecdis.3c00138] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Indexed: 08/29/2023]
Abstract
With the resistance increasing to current antimalarial medicines, there is an urgent need to discover new drug targets and to develop new medicines against these targets. We therefore screened the Open Global Health Library of Merck KGaA, Darmstadt, Germany, of 250 compounds against the asexual blood stage of the deadliest malarial parasite Plasmodium falciparum, from which eight inhibitors with low micromolar potency were found. Due to its combined potencies against parasite growth and inhibition of red blood cell invasion, the pyridyl-furan compound OGHL250 was prioritized for further optimization. The potency of the series lead compound (WEHI-518) was improved 250-fold to low nanomolar levels against parasite blood-stage growth. Parasites selected for resistance to a related compound, MMV396797, were also resistant to WEHI-518 as well as KDU731, an inhibitor of the phosphatidylinositol kinase PfPI4KIIIB, suggesting that this kinase is the target of the pyridyl-furan series. Inhibition of PfPI4KIIIB blocks multiple stages of the parasite's life cycle and other potent inhibitors are currently under preclinical development. MMV396797-resistant parasites possess an E1316D mutation in PfPKI4IIIB that clusters with known resistance mutations of other inhibitors of the kinase. Building upon earlier studies that showed that PfPI4KIIIB inhibitors block the development of the invasive merozoite parasite stage, we show that members of the pyridyl-furan series also block invasion and/or the conversion of merozoites into ring-stage intracellular parasites through inhibition of protein secretion and export into red blood cells.
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Affiliation(s)
- Dawson B. Ling
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
| | - William Nguyen
- The Walter and Eliza Hall Institute of
Medical Research, Melbourne, Victoria3052,
Australia
- Department of Medical Biology, The
University of Melbourne, Parkville, Victoria3010,
Australia
| | - Oliver Looker
- Burnet Institute,
Melbourne, Victoria3004, Australia
| | - Zahra Razook
- Burnet Institute,
Melbourne, Victoria3004, Australia
- School of Medicine and Institute for Mental and
Physical Health and Clinical Translation, Deakin University,
Waurn Ponds, Victoria3216, Australia
| | - Kirsty McCann
- Burnet Institute,
Melbourne, Victoria3004, Australia
- School of Medicine and Institute for Mental and
Physical Health and Clinical Translation, Deakin University,
Waurn Ponds, Victoria3216, Australia
| | - Alyssa E. Barry
- Burnet Institute,
Melbourne, Victoria3004, Australia
- School of Medicine and Institute for Mental and
Physical Health and Clinical Translation, Deakin University,
Waurn Ponds, Victoria3216, Australia
| | - Christian Scheurer
- Swiss Tropical and Public Health
Institute, Allschwil, 4123Switzerland
- University of Basel, Basel,
4001Switzerland
| | - Sergio Wittlin
- Swiss Tropical and Public Health
Institute, Allschwil, 4123Switzerland
- University of Basel, Basel,
4001Switzerland
| | - Mufuliat Toyin Famodimu
- Department of Infection Biology, Faculty of Infectious
Diseases, London School of Hygiene and Tropical Medicine, Kepel
Street, London, WC1E 7HT, U.K.
| | - Michael J Delves
- Department of Infection Biology, Faculty of Infectious
Diseases, London School of Hygiene and Tropical Medicine, Kepel
Street, London, WC1E 7HT, U.K.
| | - Hayley E. Bullen
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
| | - Brendan S. Crabb
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
- Department of Immunology and Pathology,
Monash University, Melbourne, Victoria3800,
Australia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of
Medical Research, Melbourne, Victoria3052,
Australia
- Department of Medical Biology, The
University of Melbourne, Parkville, Victoria3010,
Australia
| | - Paul R. Gilson
- Burnet Institute,
Melbourne, Victoria3004, Australia
- Department of Microbiology and Immunology,
University of Melbourne, Melbourne, Victoria3010,
Australia
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2
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Jonsdottir TK, Elsworth B, Cobbold S, Gabriela M, Ploeger E, Parkyn Schneider M, Charnaud SC, Dans MG, McConville M, Bullen HE, Crabb BS, Gilson PR. PTEX helps efficiently traffic haemoglobinases to the food vacuole in Plasmodium falciparum. PLoS Pathog 2023; 19:e1011006. [PMID: 37523385 PMCID: PMC10414648 DOI: 10.1371/journal.ppat.1011006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 08/10/2023] [Accepted: 07/16/2023] [Indexed: 08/02/2023] Open
Abstract
A key element of Plasmodium biology and pathogenesis is the trafficking of ~10% of the parasite proteome into the host red blood cell (RBC) it infects. To cross the parasite-encasing parasitophorous vacuole membrane, exported proteins utilise a channel-forming protein complex termed the Plasmodium translocon of exported proteins (PTEX). PTEX is obligatory for parasite survival, both in vitro and in vivo, suggesting that at least some exported proteins have essential metabolic functions. However, to date only one essential PTEX-dependent process, the new permeability pathways, has been described. To identify other essential PTEX-dependant proteins/processes, we conditionally knocked down the expression of one of its core components, PTEX150, and examined which pathways were affected. Surprisingly, the food vacuole mediated process of haemoglobin (Hb) digestion was substantially perturbed by PTEX150 knockdown. Using a range of transgenic parasite lines and approaches, we show that two major Hb proteases; falcipain 2a and plasmepsin II, interact with PTEX core components, implicating the translocon in the trafficking of Hb proteases. We propose a model where these proteases are translocated into the PV via PTEX in order to reach the cytostome, located at the parasite periphery, prior to food vacuole entry. This work offers a second mechanistic explanation for why PTEX function is essential for growth of the parasite within its host RBC.
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Affiliation(s)
- Thorey K. Jonsdottir
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Brendan Elsworth
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Simon Cobbold
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Melbourne, Australia
| | - Mikha Gabriela
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- School of Medicine, Deakin University, Geelong, Australia
| | - Ellen Ploeger
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | | | - Sarah C. Charnaud
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Madeline G. Dans
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Malcolm McConville
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Melbourne, Australia
| | - Hayley E. Bullen
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
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3
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Looker O, Dans MG, Bullen HE, Sleebs BE, Crabb BS, Gilson PR. The Medicines for Malaria Venture Malaria Box contains inhibitors of protein secretion in
Plasmodium falciparum
blood stage parasites. Traffic 2022; 23:442-461. [PMID: 36040075 PMCID: PMC9543830 DOI: 10.1111/tra.12862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 05/04/2022] [Revised: 07/17/2022] [Accepted: 07/26/2022] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum parasites which cause malaria, traffic hundreds of proteins into the red blood cells (RBCs) they infect. These exported proteins remodel their RBCs enabling host immune evasion through processes such as cytoadherence that greatly assist parasite survival. As resistance to all current antimalarial compounds is rising new compounds need to be identified and those that could inhibit parasite protein secretion and export would both rapidly reduce parasite virulence and ultimately lead to parasite death. To identify compounds that inhibit protein export we used transgenic parasites expressing an exported nanoluciferase reporter to screen the Medicines for Malaria Venture Malaria Box of 400 antimalarial compounds with mostly unknown targets. The most potent inhibitor identified in this screen was MMV396797 whose application led to export inhibition of both the reporter and endogenous exported proteins. MMV396797 mediated blockage of protein export and slowed the rigidification and cytoadherence of infected RBCs—modifications which are both mediated by parasite‐derived exported proteins. Overall, we have identified a new protein export inhibitor in P. falciparum whose target though unknown, could be developed into a future antimalarial that rapidly inhibits parasite virulence before eliminating parasites from the host.
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Affiliation(s)
| | - Madeline G. Dans
- Burnet Institute Melbourne Australia
- School of Medicine Deakin University Geelong Australia
| | - Hayley E. Bullen
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical Research Parkville Victoria Australia
- Department of Medical Biology The University of Melbourne Parkville Victoria Australia
| | - Brendan S. Crabb
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
- Department of Immunology and Pathology Monash University Melbourne Australia
| | - Paul R. Gilson
- Burnet Institute Melbourne Australia
- Department of Immunology and Microbiology University of Melbourne Melbourne Australia
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4
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Bullen HE, Sanders PR, Dans MG, Jonsdottir TK, Riglar DT, Looker O, Palmer CS, Kouskousis B, Charnaud SC, Triglia T, Gabriela M, Schneider MP, Chan J, de Koning‐Ward TF, Baum J, Kazura JW, Beeson JG, Cowman AF, Gilson PR, Crabb BS. The
Plasmodium falciparum
parasitophorous vacuole protein
P113
interacts with the parasite protein export machinery and maintains normal vacuole architecture. Mol Microbiol 2022; 117:1245-1262. [PMID: 35403274 PMCID: PMC9544671 DOI: 10.1111/mmi.14904] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/31/2022] [Accepted: 04/05/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Hayley E. Bullen
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | | | - Madeline G. Dans
- Burnet Institute 85 Commercial Road Prahran Australia
- School of Medicine Deakin University Waurn Ponds Victoria Australia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
| | - Thorey K. Jonsdottir
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | - David T. Riglar
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
- Imperial College London Department of Infectious Diseases, South Kensington Campus, SW72AZ UK
| | - Oliver Looker
- Burnet Institute 85 Commercial Road Prahran Australia
| | - Catherine S. Palmer
- Burnet Institute 85 Commercial Road Prahran Australia
- Bio21, 30 Road Parkville Flemington Australia
| | | | - Sarah C. Charnaud
- Burnet Institute 85 Commercial Road Prahran Australia
- WHO Geneva Switzerland
| | - Tony Triglia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
| | - Mikha Gabriela
- Burnet Institute 85 Commercial Road Prahran Australia
- School of Medicine Deakin University Waurn Ponds Victoria Australia
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
| | | | - Jo‐Anne Chan
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
| | | | - Jake Baum
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
- Imperial College London Department of Infectious Diseases, South Kensington Campus, SW72AZ UK
| | - James W. Kazura
- Centre for Global Health and Diseases Case Western Reserve University Cleveland Ohio USA
| | - James G. Beeson
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Medicine University of Melbourne Parkville Victoria Australia
- Department of Immunology, Central clinical school Monash University Melbourne Victoria Australia
| | - Alan F. Cowman
- Walter and Eliza Hall Institute 1G Royal Parade Parkville Australia
- Department of Medical Biology University of Melbourne Parkville Australia
| | - Paul R. Gilson
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
| | - Brendan S. Crabb
- Burnet Institute 85 Commercial Road Prahran Australia
- Department of Microbiology and Immunology University of Melbourne Parkville Australia
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5
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Gabriela M, Matthews KM, Boshoven C, Kouskousis B, Jonsdottir TK, Bullen HE, Modak J, Steer DL, Sleebs BE, Crabb BS, de Koning-Ward TF, Gilson PR. A revised mechanism for how Plasmodium falciparum recruits and exports proteins into its erythrocytic host cell. PLoS Pathog 2022; 18:e1009977. [PMID: 35192672 PMCID: PMC8896661 DOI: 10.1371/journal.ppat.1009977] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [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: 09/21/2021] [Revised: 03/04/2022] [Accepted: 02/10/2022] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum exports ~10% of its proteome into its host erythrocyte to modify the host cell's physiology. The Plasmodium export element (PEXEL) motif contained within the N-terminus of most exported proteins directs the trafficking of those proteins into the erythrocyte. To reach the host cell, the PEXEL motif of exported proteins is processed by the endoplasmic reticulum (ER) resident aspartyl protease plasmepsin V. Then, following secretion into the parasite-encasing parasitophorous vacuole, the mature exported protein must be unfolded and translocated across the parasitophorous vacuole membrane by the Plasmodium translocon of exported proteins (PTEX). PTEX is a protein-conducting channel consisting of the pore-forming protein EXP2, the protein unfoldase HSP101, and structural component PTEX150. The mechanism of how exported proteins are specifically trafficked from the parasite's ER following PEXEL cleavage to PTEX complexes on the parasitophorous vacuole membrane is currently not understood. Here, we present evidence that EXP2 and PTEX150 form a stable subcomplex that facilitates HSP101 docking. We also demonstrate that HSP101 localises both within the parasitophorous vacuole and within the parasite's ER throughout the ring and trophozoite stage of the parasite, coinciding with the timeframe of protein export. Interestingly, we found that HSP101 can form specific interactions with model PEXEL proteins in the parasite's ER, irrespective of their PEXEL processing status. Collectively, our data suggest that HSP101 recognises and chaperones PEXEL proteins from the ER to the parasitophorous vacuole and given HSP101's specificity for the EXP2-PTEX150 subcomplex, this provides a mechanism for how exported proteins are specifically targeted to PTEX for translocation into the erythrocyte.
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Affiliation(s)
- Mikha Gabriela
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- School of Medicine, Deakin University, Geelong, Australia
| | - Kathryn M. Matthews
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - Cas Boshoven
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Betty Kouskousis
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Thorey K. Jonsdottir
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Hayley E. Bullen
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Joyanta Modak
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - David L. Steer
- Monash Biomedical Proteomics and Metabolomics Facility, Monash University, Melbourne, Australia
| | - Brad E. Sleebs
- ACRF Chemical Biology Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Tania F. de Koning-Ward
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- * E-mail:
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6
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Jonsdottir TK, Counihan NA, Modak JK, Kouskousis B, Sanders PR, Gabriela M, Bullen HE, Crabb BS, de Koning-Ward TF, Gilson PR. Characterisation of complexes formed by parasite proteins exported into the host cell compartment of Plasmodium falciparum infected red blood cells. Cell Microbiol 2021; 23:e13332. [PMID: 33774908 PMCID: PMC8365696 DOI: 10.1111/cmi.13332] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 12/11/2022]
Abstract
During its intraerythrocytic life cycle, the human malaria parasite Plasmodium falciparum supplements its nutritional requirements by scavenging substrates from the plasma through the new permeability pathways (NPPs) installed in the red blood cell (RBC) membrane. Parasite proteins of the RhopH complex: CLAG3, RhopH2, RhopH3, have been implicated in NPP activity. Here, we studied 13 exported proteins previously hypothesised to interact with RhopH2, to study their potential contribution to the function of NPPs. NPP activity assays revealed that the 13 proteins do not appear to be individually important for NPP function, as conditional knockdown of these proteins had no effect on sorbitol uptake. Intriguingly, reciprocal immunoprecipitation assays showed that five of the 13 proteins interact with all members of the RhopH complex, with PF3D7_1401200 showing the strongest association. Mass spectrometry‐based proteomics further identified new protein complexes; a cytoskeletal complex and a Maurer's clefts/J‐dot complex, which overall helps clarify protein–protein interactions within the infected RBC (iRBC) and is suggestive of the potential trafficking route of the RhopH complex itself to the RBC membrane.
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Affiliation(s)
- Thorey K Jonsdottir
- Burnet Institute, Melbourne, Australia.,Department of Microbiology and Immunology, University of Melbourne, Melbourne, Australia
| | | | - Joyanta K Modak
- School of Medicine, Deakin University, Waurn Ponds, Australia
| | - Betty Kouskousis
- Burnet Institute, Melbourne, Australia.,Monash Micro-imaging, Monash University, Melbourne, Australia
| | | | - Mikha Gabriela
- Burnet Institute, Melbourne, Australia.,School of Medicine, Deakin University, Waurn Ponds, Australia
| | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Australia.,Department of Microbiology and Immunology, University of Melbourne, Melbourne, Australia.,Department of Microbiology, Monash University, Melbourne, Australia
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7
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Gilson PR, Kumarasingha R, Thompson J, Zhang X, Penington JS, Kalhor R, Bullen HE, Lehane AM, Dans MG, de Koning-Ward TF, Holien JK, Soares da Costa TP, Hulett MD, Buskes MJ, Crabb BS, Kirk K, Papenfuss AT, Cowman AF, Abbott BM. A 4-cyano-3-methylisoquinoline inhibitor of Plasmodium falciparum growth targets the sodium efflux pump PfATP4. Sci Rep 2019; 9:10292. [PMID: 31311978 PMCID: PMC6635429 DOI: 10.1038/s41598-019-46500-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 02/15/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022] Open
Abstract
We developed a novel series of antimalarial compounds based on a 4-cyano-3-methylisoquinoline. Our lead compound MB14 achieved modest inhibition of the growth in vitro of the human malaria parasite, Plasmodium falciparum. To identify its biological target we selected for parasites resistant to MB14. Genome sequencing revealed that all resistant parasites bore a single point S374R mutation in the sodium (Na+) efflux transporter PfATP4. There are many compounds known to inhibit PfATP4 and some are under preclinical development. MB14 was shown to inhibit Na+ dependent ATPase activity in parasite membranes, consistent with the compound targeting PfATP4 directly. PfATP4 inhibitors cause swelling and lysis of infected erythrocytes, attributed to the accumulation of Na+ inside the intracellular parasites and the resultant parasite swelling. We show here that inhibitor-induced lysis of infected erythrocytes is dependent upon the parasite protein RhopH2, a component of the new permeability pathways that are induced by the parasite in the erythrocyte membrane. These pathways mediate the influx of Na+ into the infected erythrocyte and their suppression via RhopH2 knockdown limits the accumulation of Na+ within the parasite hence protecting the infected erythrocyte from lysis. This study reveals a role for the parasite-induced new permeability pathways in the mechanism of action of PfATP4 inhibitors.
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Affiliation(s)
- Paul R Gilson
- Burnet Institute, Melbourne, Victoria, 3004, Australia. .,Monash University, Melbourne, Victoria, 3800, Australia.
| | | | - Jennifer Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia
| | - Xinxin Zhang
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | | | - Robabeh Kalhor
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,School of Medicine, Deakin University, Waurn Ponds, Victoria, 3216, Australia
| | | | - Jessica K Holien
- St. Vincent's Institute of Medical Research, Melbourne, Victoria, 3065, Australia
| | | | - Mark D Hulett
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,Monash University, Melbourne, Victoria, 3800, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Anthony T Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
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8
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Bullen HE, Bisio H, Soldati-Favre D. The triumvirate of signaling molecules controlling Toxoplasma microneme exocytosis: Cyclic GMP, calcium, and phosphatidic acid. PLoS Pathog 2019; 15:e1007670. [PMID: 31121005 PMCID: PMC6532924 DOI: 10.1371/journal.ppat.1007670] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
To elicit effective invasion and egress from infected cells, obligate intracellular parasites of the phylum Apicomplexa rely on the timely and spatially controlled exocytosis of specialized secretory organelles termed the micronemes. The effector molecules and signaling events underpinning this process are intricate; however, recent advances within the field of Toxoplasma gondii research have facilitated a broader understanding as well as a more integrated view of this complex cascade of events and have unraveled the importance of phosphatidic acid (PA) as a lipid mediator at multiple steps in this process.
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Affiliation(s)
- Hayley E. Bullen
- Burnet Institute, Melbourne, Victoria, Australia
- * E-mail: (HEB); (DS-F)
| | - Hugo Bisio
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland
- * E-mail: (HEB); (DS-F)
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9
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Charnaud SC, Jonsdottir TK, Sanders PR, Bullen HE, Dickerman BK, Kouskousis B, Palmer CS, Pietrzak HM, Laumaea AE, Erazo AB, McHugh E, Tilley L, Crabb BS, Gilson PR. Spatial organization of protein export in malaria parasite blood stages. Traffic 2018; 19:605-623. [DOI: 10.1111/tra.12577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 12/29/2022]
Affiliation(s)
| | - Thorey K. Jonsdottir
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
| | | | | | | | - Betty Kouskousis
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | - Catherine S. Palmer
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | | | | | | | - Emma McHugh
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Brendan S. Crabb
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
| | - Paul R. Gilson
- Burnet Institute; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
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10
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Counihan NA, Chisholm SA, Bullen HE, Srivastava A, Sanders PR, Jonsdottir TK, Weiss GE, Ghosh S, Crabb BS, Creek DJ, Gilson PR, de Koning-Ward TF. Plasmodium falciparum parasites deploy RhopH2 into the host erythrocyte to obtain nutrients, grow and replicate. eLife 2017; 6. [PMID: 28252383 PMCID: PMC5365316 DOI: 10.7554/elife.23217] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [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: 11/12/2016] [Accepted: 02/26/2017] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum parasites, the causative agents of malaria, modify their host erythrocyte to render them permeable to supplementary nutrient uptake from the plasma and for removal of toxic waste. Here we investigate the contribution of the rhoptry protein RhopH2, in the formation of new permeability pathways (NPPs) in Plasmodium-infected erythrocytes. We show RhopH2 interacts with RhopH1, RhopH3, the erythrocyte cytoskeleton and exported proteins involved in host cell remodeling. Knockdown of RhopH2 expression in cycle one leads to a depletion of essential vitamins and cofactors and decreased de novo synthesis of pyrimidines in cycle two. There is also a significant impact on parasite growth, replication and transition into cycle three. The uptake of solutes that use NPPs to enter erythrocytes is also reduced upon RhopH2 knockdown. These findings provide direct genetic support for the contribution of the RhopH complex in NPP activity and highlight the importance of NPPs to parasite survival.
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Affiliation(s)
| | | | | | - Anubhav Srivastava
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | | | - Thorey K Jonsdottir
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia
| | | | - Sreejoyee Ghosh
- School of Medicine, Deakin University, Waurn Ponds, Australia
| | - Brendan S Crabb
- Burnet Institute, Melbourne, Australia.,Department of Medicine, University of Melbourne, Parkville, Australia.,Monash University, Melbourne, Australia
| | - Darren J Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, Australia.,Monash University, Melbourne, Australia
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11
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Gilson PR, Tan C, Jarman KE, Lowes KN, Curtis JM, Nguyen W, Di Rago AE, Bullen HE, Prinz B, Duffy S, Baell JB, Hutton CA, Jousset Subroux H, Crabb BS, Avery VM, Cowman AF, Sleebs BE. Optimization of 2-Anilino 4-Amino Substituted Quinazolines into Potent Antimalarial Agents with Oral in Vivo Activity. J Med Chem 2017; 60:1171-1188. [PMID: 28080063 DOI: 10.1021/acs.jmedchem.6b01673] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Novel antimalarial therapeutics that target multiple stages of the parasite lifecycle are urgently required to tackle the emerging problem of resistance with current drugs. Here, we describe the optimization of the 2-anilino quinazoline class as antimalarial agents. The class, identified from publicly available antimalarial screening data, was optimized to generate lead compounds that possess potent antimalarial activity against P. falciparum parasites comparable to the known antimalarials, chloroquine and mefloquine. During the optimization process, we defined the functionality necessary for activity and improved in vitro metabolism and solubility. The resultant lead compounds possess potent activity against a multidrug resistant strain of P. falciparum and arrest parasites at the ring phase of the asexual stage and also gametocytogensis. Finally, we show that the lead compounds are orally efficacious in a 4 day murine model of malaria disease burden.
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Affiliation(s)
- Paul R Gilson
- Macfarlane Burnet Institute for Medical Research and Public Health , Melbourne, 3004, Australia.,Monash University , Clayton, Victoria 3800, Australia
| | - Cyrus Tan
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
| | - Kate E Jarman
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
| | - Kym N Lowes
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
| | - Joan M Curtis
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia
| | - William Nguyen
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
| | - Adrian E Di Rago
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia
| | - Hayley E Bullen
- Macfarlane Burnet Institute for Medical Research and Public Health , Melbourne, 3004, Australia
| | - Boris Prinz
- Macfarlane Burnet Institute for Medical Research and Public Health , Melbourne, 3004, Australia
| | - Sandra Duffy
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University , Nathan, Queensland 4111, Australia
| | - Jonathan B Baell
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
| | - Craig A Hutton
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , Parkville, Victoria 3010, Australia
| | - Helene Jousset Subroux
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
| | - Brendan S Crabb
- Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia.,Macfarlane Burnet Institute for Medical Research and Public Health , Melbourne, 3004, Australia.,Monash University , Clayton, Victoria 3800, Australia
| | - Vicky M Avery
- Discovery Biology, Eskitis Institute for Drug Discovery, Griffith University , Nathan, Queensland 4111, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research , Parkville 3052, Australia.,Department of Medical Biology, The University of Melbourne , Parkville 3010, Australia
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12
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Littler DR, Bullen HE, Harvey KL, Beddoe T, Crabb BS, Rossjohn J, Gilson PR. Disrupting the Allosteric Interaction between the Plasmodium falciparum cAMP-dependent Kinase and Its Regulatory Subunit. J Biol Chem 2016; 291:25375-25386. [PMID: 27738107 DOI: 10.1074/jbc.m116.750174] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 09/27/2016] [Indexed: 11/06/2022] Open
Abstract
The ubiquitous second messenger cAMP mediates signal transduction processes in the malarial parasite that regulate host erythrocyte invasion and the proliferation of merozoites. In Plasmodium falciparum, the central receptor for cAMP is the single regulatory subunit (R) of protein kinase A (PKA). To aid the development of compounds that can selectively dysregulate parasite PKA signaling, we solved the structure of the PKA regulatory subunit in complex with cAMP and a related analogue that displays antimalarial activity, (Sp)-2-Cl-cAMPS. Prior to signaling, PKA-R holds the kinase's catalytic subunit (C) in an inactive state by exerting an allosteric inhibitory effect. When two cAMP molecules bind to PKA-R, they stabilize a structural conformation that facilitates its dissociation, freeing PKA-C to phosphorylate downstream substrates such as apical membrane antigen 1. Although PKA activity was known to be necessary for erythrocytic proliferation, we show that uncontrolled induction of PKA activity using membrane-permeable agonists is equally disruptive to growth.
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Affiliation(s)
- Dene R Littler
- From the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, and
| | | | - Katherine L Harvey
- the Burnet Institute, Melbourne, Victoria 3004, Australia.,the Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Travis Beddoe
- the Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia, and
| | - Brendan S Crabb
- From the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, and.,the Burnet Institute, Melbourne, Victoria 3004, Australia.,the Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Jamie Rossjohn
- From the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, and.,the Institute of Infection and Immunity, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN Wales, United Kingdom.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Paul R Gilson
- From the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, and .,the Burnet Institute, Melbourne, Victoria 3004, Australia
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13
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Bullen HE, Soldati-Favre D. A central role for phosphatidic acid as a lipid mediator of regulated exocytosis in apicomplexa. FEBS Lett 2016; 590:2469-81. [PMID: 27403735 DOI: 10.1002/1873-3468.12296] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/10/2016] [Accepted: 07/11/2016] [Indexed: 11/08/2022]
Abstract
Lipids are commonly known for the structural roles they play, however, the specific contribution of different lipid classes to wide-ranging signalling pathways is progressively being unravelled. Signalling lipids and their associated effector proteins are emerging as significant contributors to a vast array of effector functions within cells, including essential processes such as membrane fusion and vesicle exocytosis. Many phospholipids have signalling capacity, however, this review will focus on phosphatidic acid (PA) and the enzymes implicated in its production from diacylglycerol (DAG) and phosphatidylcholine (PC): DGK and PLD respectively. PA is a negatively charged, cone-shaped lipid identified as a key mediator in specific membrane fusion and vesicle exocytosis events in a variety of mammalian cells, and has recently been implicated in specialised secretory organelle exocytosis in apicomplexan parasites. This review summarises the recent work implicating a role for PA regulation in exocytosis in various cell types. We will discuss how these signalling events are linked to pathogenesis in the phylum Apicomplexa.
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14
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Elsworth B, Sanders PR, Nebl T, Batinovic S, Kalanon M, Nie CQ, Charnaud SC, Bullen HE, de Koning Ward TF, Tilley L, Crabb BS, Gilson PR. Proteomic analysis reveals novel proteins associated with the Plasmodium protein exporter PTEX and a loss of complex stability upon truncation of the core PTEX component, PTEX150. Cell Microbiol 2016; 18:1551-1569. [PMID: 27019089 DOI: 10.1111/cmi.12596] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 03/11/2016] [Accepted: 03/22/2016] [Indexed: 11/28/2022]
Abstract
The Plasmodium translocon for exported proteins (PTEX) has been established as the machinery responsible for the translocation of all classes of exported proteins beyond the parasitophorous vacuolar membrane of the intraerythrocytic malaria parasite. Protein export, particularly in the asexual blood stage, is crucial for parasite survival as exported proteins are involved in remodelling the host cell, an essential process for nutrient uptake, waste removal and immune evasion. Here, we have truncated the conserved C-terminus of one of the essential PTEX components, PTEX150, in Plasmodium falciparum in an attempt to create mutants of reduced functionality. Parasites tolerated C-terminal truncations of up to 125 amino acids with no reduction in growth, protein export or the establishment of new permeability pathways. Quantitative proteomic approaches however revealed a decrease in other PTEX subunits associating with PTEX150 in truncation mutants, suggesting a role for the C-terminus of PTEX150 in regulating PTEX stability. Our analyses also reveal three previously unreported PTEX-associated proteins, namely PV1, Pf113 and Hsp70-x (respective PlasmoDB numbers; PF3D7_1129100, PF3D7_1420700 and PF3D7_0831700) and demonstrate that core PTEX proteins exist in various distinct multimeric forms outside the major complex.
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Affiliation(s)
- Brendan Elsworth
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia.,Monash University, Melbourne, VIC, 3800, Australia
| | - Paul R Sanders
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Thomas Nebl
- Walter & Eliza Hall Institute, Melbourne, VIC, 3052, Australia
| | - Steven Batinovic
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Melbourne, VIC, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | | | - Catherine Q Nie
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Sarah C Charnaud
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia.,Monash University, Melbourne, VIC, 3800, Australia
| | - Hayley E Bullen
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | | | - Leann Tilley
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Melbourne, VIC, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Brendan S Crabb
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia.,Monash University, Melbourne, VIC, 3800, Australia.,University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Paul R Gilson
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia. .,Monash University, Melbourne, VIC, 3800, Australia.
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15
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Kemp LE, Rusch M, Adibekian A, Bullen HE, Graindorge A, Freymond C, Rottmann M, Braun-Breton C, Baumeister S, Porfetye AT, Vetter IR, Hedberg C, Soldati-Favre D. Characterization of a serine hydrolase targeted by acyl-protein thioesterase inhibitors in Toxoplasma gondii. J Biol Chem 2013; 288:27002-27018. [PMID: 23913689 DOI: 10.1074/jbc.m113.460709] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In eukaryotic organisms, cysteine palmitoylation is an important reversible modification that impacts protein targeting, folding, stability, and interactions with partners. Evidence suggests that protein palmitoylation contributes to key biological processes in Apicomplexa with the recent palmitome of the malaria parasite Plasmodium falciparum reporting over 400 substrates that are modified with palmitate by a broad range of protein S-acyl transferases. Dynamic palmitoylation cycles require the action of an acyl-protein thioesterase (APT) that cleaves palmitate from substrates and conveys reversibility to this posttranslational modification. In this work, we identified candidates for APT activity in Toxoplasma gondii. Treatment of parasites with low micromolar concentrations of β-lactone- or triazole urea-based inhibitors that target human APT1 showed varied detrimental effects at multiple steps of the parasite lytic cycle. The use of an activity-based probe in combination with these inhibitors revealed the existence of several serine hydrolases that are targeted by APT1 inhibitors. The active serine hydrolase, TgASH1, identified as the homologue closest to human APT1 and APT2, was characterized further. Biochemical analysis of TgASH1 indicated that this enzyme cleaves substrates with a specificity similar to APTs, and homology modeling points toward an APT-like enzyme. TgASH1 is dispensable for parasite survival, which indicates that the severe effects observed with the β-lactone inhibitors are caused by the inhibition of non-TgASH1 targets. Other ASH candidates for APT activity were functionally characterized, and one of them was found to be resistant to gene disruption due to the potential essential nature of the protein.
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Affiliation(s)
- Louise E Kemp
- Department of Microbiology and Molecular Medicine, University Medical Center (CMU), University of Geneva, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland
| | | | - Alexander Adibekian
- Department of Biochemistry, Sciences II, University of Geneva, Quai Ernest Ansermet 30, CH-1211 Geneva, Switzerland
| | - Hayley E Bullen
- Department of Microbiology and Molecular Medicine, University Medical Center (CMU), University of Geneva, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland
| | - Arnault Graindorge
- Department of Microbiology and Molecular Medicine, University Medical Center (CMU), University of Geneva, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland
| | - Céline Freymond
- Department of Parasite Chemotherapy, Swiss Tropical and Public Health Institute, Socinstrasse 57, P. O. Box, CH-4002 Basel, Switzerland; University of Basel, CH-4003 Basel, Switzerland
| | - Matthias Rottmann
- Department of Parasite Chemotherapy, Swiss Tropical and Public Health Institute, Socinstrasse 57, P. O. Box, CH-4002 Basel, Switzerland; University of Basel, CH-4003 Basel, Switzerland
| | | | - Stefan Baumeister
- Departments of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Arthur T Porfetye
- Departments of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Ingrid R Vetter
- Departments of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | | | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University Medical Center (CMU), University of Geneva, Rue Michel-Servet 1, CH-1211 Geneva, Switzerland.
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16
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Bullen HE, Crabb BS, Gilson PR. Recent insights into the export of PEXEL/HTS-motif containing proteins in Plasmodium parasites. Curr Opin Microbiol 2012; 15:699-704. [DOI: 10.1016/j.mib.2012.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 09/22/2012] [Accepted: 09/25/2012] [Indexed: 10/27/2022]
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17
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Bullen HE, Charnaud SC, Kalanon M, Riglar DT, Dekiwadia C, Kangwanrangsan N, Torii M, Tsuboi T, Baum J, Ralph SA, Cowman AF, de Koning-Ward TF, Crabb BS, Gilson PR. Biosynthesis, localization, and macromolecular arrangement of the Plasmodium falciparum translocon of exported proteins (PTEX). J Biol Chem 2012; 287:7871-84. [PMID: 22253438 DOI: 10.1074/jbc.m111.328591] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To survive within its host erythrocyte, Plasmodium falciparum must export hundreds of proteins across both its parasite plasma membrane and surrounding parasitophorous vacuole membrane, most of which are likely to use a protein complex known as PTEX (Plasmodium translocon of exported proteins). PTEX is a putative protein trafficking machinery responsible for the export of hundreds of proteins across the parasitophorous vacuole membrane and into the human host cell. Five proteins are known to comprise the PTEX complex, and in this study, three of the major stoichiometric components are investigated including HSP101 (a AAA(+) ATPase), a protein of no known function termed PTEX150, and the apparent membrane component EXP2. We show that these proteins are synthesized in the preceding schizont stage (PTEX150 and HSP101) or even earlier in the life cycle (EXP2), and before invasion these components reside within the dense granules of invasive merozoites. From these apical organelles, the protein complex is released into the host cell where it resides with little turnover in the parasitophorous vacuole membrane for most of the remainder of the following cell cycle. At this membrane, PTEX is arranged in a stable macromolecular complex of >1230 kDa that includes an ∼600-kDa apparently homo-oligomeric complex of EXP2 that can be separated from the remainder of the PTEX complex using non-ionic detergents. Two different biochemical methods undertaken here suggest that PTEX components associate as EXP2-PTEX150-HSP101, with EXP2 associating with the vacuolar membrane. Collectively, these data support the hypothesis that EXP2 oligomerizes and potentially forms the putative membrane-spanning pore to which the remainder of the PTEX complex is attached.
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Affiliation(s)
- Hayley E Bullen
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria 3004, Australia
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18
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Bullen HE, Tonkin CJ, O'Donnell RA, Tham WH, Papenfuss AT, Gould S, Cowman AF, Crabb BS, Gilson PR. A novel family of Apicomplexan glideosome-associated proteins with an inner membrane-anchoring role. J Biol Chem 2009; 284:25353-63. [PMID: 19561073 PMCID: PMC2757237 DOI: 10.1074/jbc.m109.036772] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [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] [Indexed: 11/06/2022] Open
Abstract
The phylum Apicomplexa are a group of obligate intracellular parasites responsible for a wide range of important diseases. Central to the lifecycle of these unicellular parasites is their ability to migrate through animal tissue and invade target host cells. Apicomplexan movement is generated by a unique system of gliding motility in which substrate adhesins and invasion-related proteins are pulled across the plasma membrane by an underlying actin-myosin motor. The myosins of this motor are inserted into a dual membrane layer called the inner membrane complex (IMC) that is sandwiched between the plasma membrane and an underlying cytoskeletal basket. Central to our understanding of gliding motility is the characterization of proteins residing within the IMC, but to date only a few proteins are known. We report here a novel family of six-pass transmembrane proteins, termed the GAPM family, which are highly conserved and specific to Apicomplexa. In Plasmodium falciparum and Toxoplasma gondii the GAPMs localize to the IMC where they form highly SDS-resistant oligomeric complexes. The GAPMs co-purify with the cytoskeletal alveolin proteins and also to some degree with the actin-myosin motor itself. Hence, these proteins are strong candidates for an IMC-anchoring role, either directly or indirectly tethering the motor to the cytoskeleton.
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Affiliation(s)
- Hayley E Bullen
- Macfarlane Burnet Institute for Medical Research & Public Health, Melbourne, Victoria 3004, Australia
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