1
|
Schwarzer E, Skorokhod O. Post-Translational Modifications of Proteins of Malaria Parasites during the Life Cycle. Int J Mol Sci 2024; 25:6145. [PMID: 38892332 PMCID: PMC11173270 DOI: 10.3390/ijms25116145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 05/29/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Post-translational modifications (PTMs) are essential for regulating protein functions, influencing various fundamental processes in eukaryotes. These include, but are not limited to, cell signaling, protein trafficking, the epigenetic control of gene expression, and control of the cell cycle, as well as cell proliferation, differentiation, and interactions between cells. In this review, we discuss protein PTMs that play a key role in the malaria parasite biology and its pathogenesis. Phosphorylation, acetylation, methylation, lipidation and lipoxidation, glycosylation, ubiquitination and sumoylation, nitrosylation and glutathionylation, all of which occur in malarial parasites, are reviewed. We provide information regarding the biological significance of these modifications along all phases of the complex life cycle of Plasmodium spp. Importantly, not only the parasite, but also the host and vector protein PTMs are often crucial for parasite growth and development. In addition to metabolic regulations, protein PTMs can result in epitopes that are able to elicit both innate and adaptive immune responses of the host or vector. We discuss some existing and prospective results from antimalarial drug discovery trials that target various PTM-related processes in the parasite or host.
Collapse
Affiliation(s)
- Evelin Schwarzer
- Department of Oncology, University of Turin, Via Santena 5 bis, 10126 Turin, Italy;
| | - Oleksii Skorokhod
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina, 13, 10123 Turin, Italy
| |
Collapse
|
2
|
Jennison C, Armstrong JM, Dankwa DA, Hertoghs N, Kumar S, Abatiyow BA, Naung M, Minkah NK, Swearingen KE, Moritz R, Barry AE, Kappe SHI, Vaughan AM. Plasmodium GPI-anchored micronemal antigen is essential for parasite transmission through the mosquito host. Mol Microbiol 2024; 121:394-412. [PMID: 37314965 PMCID: PMC11076100 DOI: 10.1111/mmi.15078] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/03/2023] [Accepted: 05/08/2023] [Indexed: 06/16/2023]
Abstract
Plasmodium parasites, the eukaryotic pathogens that cause malaria, feature three distinct invasive forms tailored to the host environment they must navigate and invade for life cycle progression. One conserved feature of these invasive forms is the micronemes, apically oriented secretory organelles involved in egress, motility, adhesion, and invasion. Here we investigate the role of GPI-anchored micronemal antigen (GAMA), which shows a micronemal localization in all zoite forms of the rodent-infecting species Plasmodium berghei. ∆GAMA parasites are severely defective for invasion of the mosquito midgut. Once formed, oocysts develop normally, however, sporozoites are unable to egress and exhibit defective motility. Epitope-tagging of GAMA revealed tight temporal expression late during sporogony and showed that GAMA is shed during sporozoite gliding motility in a similar manner to circumsporozoite protein. Complementation of P. berghei knockout parasites with full-length P. falciparum GAMA partially restored infectivity to mosquitoes, indicating conservation of function across Plasmodium species. A suite of parasites with GAMA expressed under the promoters of CTRP, CAP380, and TRAP, further confirmed the involvement of GAMA in midgut infection, motility, and vertebrate infection. These data show GAMA's involvement in sporozoite motility, egress, and invasion, implicating GAMA as a regulator of microneme function.
Collapse
Affiliation(s)
- Charlie Jennison
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Janna M. Armstrong
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Dorender A. Dankwa
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Nina Hertoghs
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Biley A. Abatiyow
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Myo Naung
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Victoria, Parkville, Australia
- Department of Medical Biology, University of Melbourne, Victoria, Carlton, Australia
- Department of Global Health, University of Washington, Washington, Seattle, USA
| | - Nana K. Minkah
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
| | - Kristian E. Swearingen
- Institute of Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Victoria, Geelong, Australia
| | - Robert Moritz
- Institute of Mental and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Victoria, Geelong, Australia
| | - Alyssa E. Barry
- Department of Global Health, University of Washington, Washington, Seattle, USA
- Institute for Systems Biology, Washington, Seattle, USA
| | - Stefan H. I. Kappe
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
- Burnet Institute, Victoria, Melbourne, Australia
- Department of Pediatrics, University of Washington, Washington, Seattle, USA
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Washington, Seattle, USA
- Burnet Institute, Victoria, Melbourne, Australia
- Department of Pediatrics, University of Washington, Washington, Seattle, USA
| |
Collapse
|
3
|
Preston SP, Stutz MD, Allison CC, Nachbur U, Gouil Q, Tran BM, Duvivier V, Arandjelovic P, Cooney JP, Mackiewicz L, Meng Y, Schaefer J, Bader SM, Peng H, Valaydon Z, Rajasekaran P, Jennison C, Lopaticki S, Farrell A, Ryan M, Howell J, Croagh C, Karunakaran D, Schuster-Klein C, Murphy JM, Fifis T, Christophi C, Vincan E, Blewitt ME, Thompson A, Boddey JA, Doerflinger M, Pellegrini M. Epigenetic Silencing of RIPK3 in Hepatocytes Prevents MLKL-mediated Necroptosis From Contributing to Liver Pathologies. Gastroenterology 2022; 163:1643-1657.e14. [PMID: 36037995 DOI: 10.1053/j.gastro.2022.08.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 01/21/2023]
Abstract
BACKGROUND & AIMS Necroptosis is a highly inflammatory mode of cell death that has been implicated in causing hepatic injury including steatohepatitis/ nonalcoholic steatohepatitis (NASH); however, the evidence supporting these claims has been controversial. A comprehensive, fundamental understanding of cell death pathways involved in liver disease critically underpins rational strategies for therapeutic intervention. We sought to define the role and relevance of necroptosis in liver pathology. METHODS Several animal models of human liver pathology, including diet-induced steatohepatitis in male mice and diverse infections in both male and female mice, were used to dissect the relevance of necroptosis in liver pathobiology. We applied necroptotic stimuli to primary mouse and human hepatocytes to measure their susceptibility to necroptosis. Paired liver biospecimens from patients with NASH, before and after intervention, were analyzed. DNA methylation sequencing was also performed to investigate the epigenetic regulation of RIPK3 expression in primary human and mouse hepatocytes. RESULTS Identical infection kinetics and pathologic outcomes were observed in mice deficient in an essential necroptotic effector protein, MLKL, compared with control animals. Mice lacking MLKL were indistinguishable from wild-type mice when fed a high-fat diet to induce NASH. Under all conditions tested, we were unable to induce necroptosis in hepatocytes. We confirmed that a critical activator of necroptosis, RIPK3, was epigenetically silenced in mouse and human primary hepatocytes and rendered them unable to undergo necroptosis. CONCLUSIONS We have provided compelling evidence that necroptosis is disabled in hepatocytes during homeostasis and in the pathologic conditions tested in this study.
Collapse
Affiliation(s)
- Simon P Preston
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Michael D Stutz
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Cody C Allison
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Ueli Nachbur
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Quentin Gouil
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Bang Manh Tran
- Department of Infectious Diseases, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Valerie Duvivier
- Cardiovascular and Metabolic Disease Center for Therapeutic Innovation, SERVIER Group, Suresnes, France
| | - Philip Arandjelovic
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - James P Cooney
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Liana Mackiewicz
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Yanxiang Meng
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Jan Schaefer
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Stefanie M Bader
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Hongke Peng
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Zina Valaydon
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Pravin Rajasekaran
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Charlie Jennison
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Sash Lopaticki
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Ann Farrell
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marno Ryan
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jess Howell
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Catherine Croagh
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Denuja Karunakaran
- Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia; Monash Biomedicine Discovery Institute and Victorian Heart Institute, Monash University, Clayton, Victoria, Australia
| | - Carole Schuster-Klein
- Cardiovascular and Metabolic Disease Center for Therapeutic Innovation, SERVIER Group, Suresnes, France
| | - James M Murphy
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Theodora Fifis
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher Christophi
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Elizabeth Vincan
- Department of Infectious Diseases, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; Victorian Infectious Disease Reference Laboratory, The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia; Curtin Medical School, Curtin University, Perth, Western Australia, Australia
| | - Marnie E Blewitt
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Alexander Thompson
- Department of Gastroenterology, St. Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
| | - Justin A Boddey
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Marcel Doerflinger
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.
| | - Marc Pellegrini
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.
| |
Collapse
|
4
|
Pathak AK, Shiau JC, Franke-Fayard B, Shollenberger LM, Harn DA, Kyle DE, Murdock CC. Streamlining sporozoite isolation from mosquitoes by leveraging the dynamics of migration to the salivary glands. Malar J 2022; 21:264. [PMID: 36100902 PMCID: PMC9472382 DOI: 10.1186/s12936-022-04270-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/12/2022] [Indexed: 12/05/2022] Open
Abstract
Background Sporozoites isolated from the salivary glands of Plasmodium-infected mosquitoes are a prerequisite for several basic and pre-clinical applications. Although salivary glands are pooled to maximize sporozoite recovery, insufficient yields pose logistical and analytical hurdles; thus, predicting yields prior to isolation would be valuable. Preceding oocyst densities in the midgut is an obvious candidate. However, it is unclear whether current understanding of its relationship with sporozoite densities can be used to maximize yields, or whether it can capture the potential density-dependence in rates of sporozoite invasion of the salivary glands. Methods This study presents a retrospective analysis of Anopheles stephensi mosquitoes infected with two strains of the rodent-specific Plasmodium berghei. Mean oocyst densities were estimated in the midguts earlier in the infection (11–15 days post-blood meal), with sporozoites pooled from the salivary glands later in the infection (17–29 days). Generalized linear mixed effects models were used to determine if (1) mean oocyst densities can predict sporozoite yields from pooled salivary glands, (2) whether these densities can capture differences in rates of sporozoite invasion of salivary glands, and (3), if the interaction between oocyst densities and time could be leveraged to boost overall yields. Results The non-linear effect of mean oocyst densities confirmed the role of density-dependent constraints in limiting yields beyond certain oocyst densities. Irrespective of oocyst densities however, the continued invasion of salivary glands by the sporozoites boosted recoveries over time (17–29 days post-blood meal) for either parasite strain. Conclusions Sporozoite invasion of the salivary glands over time can be leveraged to maximize yields for P. berghei. In general, however, invasion of the salivary glands over time is a critical fitness determinant for all Plasmodium species (extrinsic incubation period, EIP). Thus, delaying sporozoite collection could, in principle, substantially reduce dissection effort for any parasite within the genus, with the results also alluding to the potential for changes in sporozoites densities over time to modify infectivity for the next host. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04270-y.
Collapse
|
5
|
Tryptophan C-mannosylation is critical for Plasmodium falciparum transmission. Nat Commun 2022; 13:4400. [PMID: 35906227 PMCID: PMC9338275 DOI: 10.1038/s41467-022-32076-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 07/07/2022] [Indexed: 11/08/2022] Open
Abstract
Tryptophan C-mannosylation stabilizes proteins bearing a thrombospondin repeat (TSR) domain in metazoans. Here we show that Plasmodium falciparum expresses a DPY19 tryptophan C-mannosyltransferase in the endoplasmic reticulum and that DPY19-deficiency abolishes C-glycosylation, destabilizes members of the TRAP adhesin family and inhibits transmission to mosquitoes. Imaging P. falciparum gametogenesis in its entirety in four dimensions using lattice light-sheet microscopy reveals defects in ΔDPY19 gametocyte egress and exflagellation. While egress is diminished, ΔDPY19 microgametes still fertilize macrogametes, forming ookinetes, but these are abrogated for mosquito infection. The gametogenesis defects correspond with destabilization of MTRAP, which we show is C-mannosylated in P. falciparum, and the ookinete defect is concordant with defective CTRP secretion on the ΔDPY19 background. Genetic complementation of DPY19 restores ookinete infectivity, sporozoite production and C-mannosylation activity. Therefore, tryptophan C-mannosylation by DPY19 ensures TSR protein quality control at two lifecycle stages for successful transmission of the human malaria parasite. Here, Lopaticki et al. show that Plasmodium falciparum expresses a Dpy19 C-mannosyltransferase in the endoplasmic reticulum that glycosylates TSR domains. Functional characterization shows that PfDpy19 plays a critical role in transmission through mosquitoes as PfDpy19-deficiency abolishes C-glycosylation and destabilizes proteins relevant for gametogenesis and oocyst formation.
Collapse
|
6
|
Ebert G, Lopaticki S, O'Neill MT, Steel RWJ, Doerflinger M, Rajasekaran P, Yang ASP, Erickson S, Ioannidis L, Arandjelovic P, Mackiewicz L, Allison C, Silke J, Pellegrini M, Boddey JA. Targeting the Extrinsic Pathway of Hepatocyte Apoptosis Promotes Clearance of Plasmodium Liver Infection. Cell Rep 2021; 30:4343-4354.e4. [PMID: 32234472 DOI: 10.1016/j.celrep.2020.03.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/30/2020] [Accepted: 03/11/2020] [Indexed: 02/08/2023] Open
Abstract
Plasmodium sporozoites infect the liver and develop into exoerythrocytic merozoites that initiate blood-stage disease. The hepatocyte molecular pathways that permit or abrogate parasite replication and merozoite formation have not been thoroughly explored, and a deeper understanding may identify therapeutic strategies to mitigate malaria. Cellular inhibitor of apoptosis (cIAP) proteins regulate cell survival and are co-opted by intracellular pathogens to support development. Here, we show that cIAP1 levels are upregulated during Plasmodium liver infection and that genetic or pharmacological targeting of cIAPs using clinical-stage antagonists preferentially kills infected hepatocytes and promotes immunity. Using gene-targeted mice, the mechanism was defined as TNF-TNFR1-mediated apoptosis via caspases 3 and 8 to clear parasites. This study reveals the importance of cIAPs to Plasmodium infection and demonstrates that host-directed antimalarial drugs can eliminate liver parasites and induce immunity while likely providing a high barrier to resistance in the parasite.
Collapse
Affiliation(s)
- Gregor Ebert
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Matthew T O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Ryan W J Steel
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Marcel Doerflinger
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Pravin Rajasekaran
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Annie S P Yang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Sara Erickson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Lisa Ioannidis
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Philip Arandjelovic
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Liana Mackiewicz
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Cody Allison
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - John Silke
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Marc Pellegrini
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia.
| |
Collapse
|
7
|
Jennison C, Lucantoni L, O'Neill MT, McConville R, Erickson SM, Cowman AF, Sleebs BE, Avery VM, Boddey JA. Inhibition of Plasmepsin V Activity Blocks Plasmodium falciparum Gametocytogenesis and Transmission to Mosquitoes. Cell Rep 2020; 29:3796-3806.e4. [PMID: 31851913 DOI: 10.1016/j.celrep.2019.11.073] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/14/2019] [Accepted: 11/15/2019] [Indexed: 12/20/2022] Open
Abstract
Plasmodium falciparum gametocytes infect mosquitoes and are responsible for malaria transmission. New interventions that block transmission could accelerate malaria elimination. Gametocytes develop within erythrocytes and activate protein export pathways that remodel the host cell. Plasmepsin V (PMV) is an aspartyl protease that is required for protein export in asexual parasites, but its function and essentiality in gametocytes has not been definitively proven, nor has PMV been assessed as a transmission-blocking drug target. Here, we show that PMV is expressed and can be inhibited specifically in P. falciparum stage I-II gametocytes. PMV inhibitors block processing and export of gametocyte effector proteins and inhibit development of stage II-V gametocytes. Gametocytogenesis in the presence of sublethal inhibitor concentrations results in stage V gametocytes that fail to infect mosquitoes. Therefore, PMV primes gametocyte effectors for export, which is essential for the development and fitness of gametocytes for transmission to mosquitoes.
Collapse
Affiliation(s)
- Charlie Jennison
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Leonardo Lucantoni
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan 4111, QLD, Australia
| | - Matthew T O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia
| | - Robyn McConville
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Sara M Erickson
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Vicky M Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan 4111, QLD, Australia
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia.
| |
Collapse
|
8
|
A malaria parasite subtilisin propeptide-like protein is a potent inhibitor of the egress protease SUB1. Biochem J 2020; 477:525-540. [PMID: 31942933 PMCID: PMC6993865 DOI: 10.1042/bcj20190918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 12/23/2022]
Abstract
Subtilisin-like serine peptidases (subtilases) play important roles in the life cycle of many organisms, including the protozoan parasites that are the causative agent of malaria, Plasmodium spp. As with other peptidases, subtilase proteolytic activity has to be tightly regulated in order to prevent potentially deleterious uncontrolled protein degradation. Maturation of most subtilases requires the presence of an N-terminal propeptide that facilitates folding of the catalytic domain. Following its proteolytic cleavage, the propeptide acts as a transient, tightly bound inhibitor until its eventual complete removal to generate active protease. Here we report the identification of a stand-alone malaria parasite propeptide-like protein, called SUB1-ProM, encoded by a conserved gene that lies in a highly syntenic locus adjacent to three of the four subtilisin-like genes in the Plasmodium genome. Template-based modelling and ab initio structure prediction showed that the SUB1-ProM core structure is most similar to the X-ray crystal structure of the propeptide of SUB1, an essential parasite subtilase that is discharged into the parasitophorous vacuole (PV) to trigger parasite release (egress) from infected host cells. Recombinant Plasmodium falciparum SUB1-ProM was found to be a fast-binding, potent inhibitor of P. falciparum SUB1, but not of the only other essential blood-stage parasite subtilase, SUB2, or of other proteases examined. Mass-spectrometry and immunofluorescence showed that SUB1-ProM is expressed in the PV of blood stage P. falciparum, where it may act as an endogenous inhibitor to regulate SUB1 activity in the parasite.
Collapse
|