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Recognition of Two Distinct Pathways for Trafficking of Proteins to the Apicoplast. mBio 2021; 12:e0263421. [PMID: 34933443 PMCID: PMC8689519 DOI: 10.1128/mbio.02634-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Prasad A, Mastud P, Patankar S. Dually localised proteins found in both the apicoplast and mitochondrion utilize the Golgi-dependent pathway for apicoplast targeting in Toxoplasma gondii. Biol Cell 2020; 113:58-78. [PMID: 33112425 DOI: 10.1111/boc.202000050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 10/07/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND INFORMATION Like other apicomplexan parasites, Toxoplasma gondii harbours a four-membraned endosymbiotic organelle - the apicoplast. Apicoplast proteins are nuclear encoded and trafficked to the organelle through the endoplasmic reticulum (ER). From the ER to the apicoplast, two distinct protein trafficking pathways can be used. One such pathway is the cell's secretory pathway involving the Golgi, whereas the other is a unique Golgi-independent pathway. Using different experimental approaches, many apicoplast proteins have been shown to utilize the Golgi-independent pathway, whereas a handful of reports show that a few proteins use the Golgi-dependent pathway. This has led to an emphasis towards the unique Golgi-independent pathway when apicoplast protein trafficking is discussed in the literature. Additionally, the molecular features that drive proteins to each pathway are not known. RESULTS In this report, we systematically test eight apicoplast proteins, using a C-terminal HDEL sequence to assess the role of the Golgi in their transport. We demonstrate that dually localised proteins of the apicoplast and mitochondrion (TgSOD2, TgTPx1/2 and TgACN/IRP) are trafficked through the Golgi, whereas proteins localised exclusively to the apicoplast are trafficked independent of the Golgi. Mutants of the dually localised proteins that localised exclusively to the apicoplast also showed trafficking through the Golgi. Phylogenetic analysis of TgSOD2, TgTPx1/2 and TgACN/IRP suggested that the evolutionary origins of TgSOD2 and TgTPx1/2 lie in the mitochondrion, whereas TgACN/IRP appears to have originated from the apicoplast. CONCLUSIONS AND SIGNIFICANCE Collectively, with these results, for the first time, we establish that the driver of the Golgi-dependent trafficking route to the apicoplast is the dual localisation of the protein to the apicoplast and the mitochondrion.
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Affiliation(s)
- Aparna Prasad
- Department of Biosciences & Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Pragati Mastud
- Department of Biosciences & Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Swati Patankar
- Department of Biosciences & Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
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Mastud P, Patankar S. An ambiguous N-terminus drives the dual targeting of an antioxidant protein Thioredoxin peroxidase (TgTPx1/2) to endosymbiotic organelles in Toxoplasma gondii. PeerJ 2019; 7:e7215. [PMID: 31346496 PMCID: PMC6642795 DOI: 10.7717/peerj.7215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/30/2019] [Indexed: 12/21/2022] Open
Abstract
Toxoplasma gondii harbors two endosymbiotic organelles: a relict plastid, the apicoplast, and a mitochondrion. The parasite expresses an antioxidant protein, thioredoxin peroxidase 1/2 (TgTPx1/2), that is dually targeted to these organelles. Nuclear-encoded proteins such as TgTPx1/2 are trafficked to the apicoplast via a secretory route through the endoplasmic reticulum (ER) and to the mitochondrion via a non-secretory pathway comprising of translocon uptake. Given the two distinct trafficking pathways for localization to the two organelles, the signals in TgTPx1/2 for this dual targeting are open areas of investigation. Here we show that the signals for apicoplast and mitochondrial trafficking lie in the N-terminal 50 amino acids of the protein and are overlapping. Interestingly, mutational analysis of the overlapping stretch shows that despite this overlap, the signals for individual organellar uptake can be easily separated. Further, deletions in the N-terminus also reveal a 10 amino acid stretch that is responsible for targeting the protein from punctate structures surrounding the apicoplast into the organelle itself. Collectively, results presented in this report suggest that an ambiguous signal sequence for organellar uptake combined with a hierarchy of recognition by the protein trafficking machinery drives the dual targeting of TgTPx1/2.
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Affiliation(s)
- Pragati Mastud
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Swati Patankar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
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Narayan A, Mastud P, Thakur V, Rathod PK, Mohmmed A, Patankar S. Heterologous expression in Toxoplasma gondii reveals a topogenic signal anchor in a Plasmodium apicoplast protein. FEBS Open Bio 2018; 8:1746-1762. [PMID: 30410855 PMCID: PMC6212639 DOI: 10.1002/2211-5463.12527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 08/24/2018] [Accepted: 09/08/2018] [Indexed: 12/27/2022] Open
Abstract
Glutathione peroxidase‐like thioredoxin peroxidase (PfTPxGl) is an antioxidant enzyme trafficked to the apicoplast, a secondary endosymbiotic organelle, in Plasmodium falciparum. Apicoplast trafficking signals usually consist of N‐terminal signal and transit peptides, but the trafficking signal of PfTPxGl appears to exhibit important differences. As transfection is a protracted process in P. falciparum, we expressed the N terminus of PfTPxGl as a GFP fusion protein in a related apicomplexan, Toxoplasma gondii, in order to dissect its trafficking signals. We show that PfTPxGl possesses an N‐terminal signal anchor that takes the protein to the endoplasmic reticulum in Toxoplasma—this is the first step in the apicoplast targeting pathway. We dissected the residues important for endomembrane system uptake, membrane anchorage, orientation, spacing, and cleavage. Protease protection assays and fluorescence complementation revealed that the C terminus of the protein lies in the ER lumen, a topology that is proposed to be retained in the apicoplast. Additionally, we examined one mutant, responsible for altered PfTPxGl targeting in Toxoplasma, in Plasmodium. This study has demonstrated that PfTPxGl belongs to an emergent class of proteins that possess signal anchors, unlike the canonical bipartite targeting signals employed for the trafficking of luminal apicoplast proteins. This work adds to the mounting evidence that the signals involved in the targeting of apicoplast membrane proteins may not be as straightforward as those of luminal proteins, and also highlights the usefulness of T. gondii as a heterologous system in certain aspects of this study, such as reducing screening time and facilitating the verification of membrane topology.
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Affiliation(s)
- Aishwarya Narayan
- Department of Biosciences and Bioengineering IIT Bombay Mumbai India
| | - Pragati Mastud
- Department of Biosciences and Bioengineering IIT Bombay Mumbai India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology New Delhi India
| | | | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology New Delhi India
| | - Swati Patankar
- Department of Biosciences and Bioengineering IIT Bombay Mumbai India
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Knockout of the peroxiredoxin 5 homologue PFAOP does not affect the artemisinin susceptibility of Plasmodium falciparum. Sci Rep 2017; 7:4410. [PMID: 28667301 PMCID: PMC5493673 DOI: 10.1038/s41598-017-04277-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 05/03/2017] [Indexed: 01/07/2023] Open
Abstract
Artemisinins are the current mainstay of malaria chemotherapy. Their exact mode of action is an ongoing matter of debate, and several factors have recently been reported to affect an early stage of artemisinin resistance of the most important human malaria parasite Plasmodium falciparum. Here, we identified a locus on chromosome 7 that affects the artemisinin susceptibility of P. falciparum in a quantitative trait locus analysis of a genetic cross between strains 7G8 and GB4. This locus includes the peroxiredoxin gene PFAOP. However, steady-state kinetic data with recombinant PfAOP do not support a direct interaction between this peroxidase and the endoperoxide artemisinin. Furthermore, neither the overexpression nor the deletion of the encoding gene affected the IC50 values for artemisinin or the oxidants diamide and tert-butyl hydroperoxide. Thus, PfAOP is dispensable for blood stage parasite survival, and the correlation between the artemisinin susceptibility and chromosome 7 is probably based on another gene within the identified locus.
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Chaudhari R, Dey V, Narayan A, Sharma S, Patankar S. Membrane and luminal proteins reach the apicoplast by different trafficking pathways in the malaria parasite Plasmodium falciparum. PeerJ 2017; 5:e3128. [PMID: 28462015 PMCID: PMC5410153 DOI: 10.7717/peerj.3128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/27/2017] [Indexed: 01/12/2023] Open
Abstract
The secretory pathway in Plasmodium falciparum has evolved to transport proteins to the host cell membrane and to an endosymbiotic organelle, the apicoplast. The latter can occur via the ER or the ER-Golgi route. Here, we study these three routes using proteins Erythrocyte Membrane Protein-1 (PfEMP1), Acyl Carrier Protein (ACP) and glutathione peroxidase-like thioredoxin peroxidase (PfTPxGl) and inhibitors of vesicular transport. As expected, the G protein-dependent vesicular fusion inhibitor AlF4− and microtubule destabilizing drug vinblastine block the trafficking of PfEMP-1, a protein secreted to the host cell membrane. However, while both PfTPxGl and ACP are targeted to the apicoplast, only ACP trafficking remains unaffected by these treatments. This implies that G protein-dependent vesicles do not play a role in classical apicoplast protein targeting. Unlike the soluble protein ACP, we show that PfTPxGl is localized to the outermost membrane of the apicoplast. Thus, the parasite apicoplast acquires proteins via two different pathways: first, the vesicular trafficking pathway appears to handle not only secretory proteins, but an apicoplast membrane protein, PfTPxGl; second, trafficking of apicoplast luminal proteins appear to be independent of G protein-coupled vesicles.
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Affiliation(s)
- Rahul Chaudhari
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Vishakha Dey
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Mumbai, Maharashtra, India
| | - Aishwarya Narayan
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Mumbai, Maharashtra, India
| | - Shobhona Sharma
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Swati Patankar
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Mumbai, Maharashtra, India
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Molecular cloning, characterization and expression profile of a glutathione peroxidase-like thioredoxin peroxidase (TPxGl) of the rodent malaria parasite Plasmodium berghei. Parasitol Int 2015; 64:282-9. [DOI: 10.1016/j.parint.2014.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 01/15/2014] [Accepted: 02/24/2014] [Indexed: 01/07/2023]
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Zíková A, Oborník M, Lukeš J. Fancy a gene? A surprisingly complex evolutionary history of peroxiredoxins. MICROBIAL CELL 2015; 2:33-37. [PMID: 28362003 PMCID: PMC5354554 DOI: 10.15698/mic2015.02.189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
While the phylum Apicomplexa includes “only” several thousand described species of obligatory parasites of animals, it may in fact be the most specious group of parasitic protists with over a million species 1. The best known representatives are Plasmodium spp., Toxoplasma gondii and Cryptosporidium spp., which belong to the most important and widespread human parasites exacting an enormous disease burden. On the other hand, dinoflagellates and colpodellids, which are monophyletic with the apicomplexans, are ecologically highly significant, as they belong to the most abundant marine protists 2. As the common ancestor of these groups was most likely a free-living photosynthesizing protist, one wonders, which evolutionary forces contributed to the dramatic transition of some of its descendants into the arguably most successful intracellular parasites? Although a range of various processes and mechanisms contributed to this transition, most likely it also involved an acquisition of genes via horizontal gene transfer (HGT), which might have provided typical characteristics of a parasitic cell, such as immune escape, nutritional dependence and the capacity to invade other cells.
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Affiliation(s)
- Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic. ; Faculty of Science, University of South Bohemia, 370 05 České Budějovice (Budweis), Czech Republic
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic. ; Faculty of Science, University of South Bohemia, 370 05 České Budějovice (Budweis), Czech Republic. ; Institute of Microbiology, Czech Academy of Sciences, 379 81 Třeboň, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic. ; Faculty of Science, University of South Bohemia, 370 05 České Budějovice (Budweis), Czech Republic. ; Canadian Institute for Advanced Research, Toronto ON, M5G 1Z8, Canada
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Vesicles bearing Toxoplasma apicoplast membrane proteins persist following loss of the relict plastid or Golgi body disruption. PLoS One 2014; 9:e112096. [PMID: 25369183 PMCID: PMC4219833 DOI: 10.1371/journal.pone.0112096] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 10/13/2014] [Indexed: 12/16/2022] Open
Abstract
Toxoplasma gondii and malaria parasites contain a unique and essential relict plastid called the apicoplast. Most apicoplast proteins are encoded in the nucleus and are transported to the organelle via the endoplasmic reticulum (ER). Three trafficking routes have been proposed for apicoplast membrane proteins: (i) vesicular trafficking from the ER to the Golgi and then to the apicoplast, (ii) contiguity between the ER membrane and the apicoplast allowing direct flow of proteins, and (iii) vesicular transport directly from the ER to the apicoplast. Previously, we identified a set of membrane proteins of the T. gondii apicoplast which were also detected in large vesicles near the organelle. Data presented here show that the large vesicles bearing apicoplast membrane proteins are not the major carriers of luminal proteins. The vesicles continue to appear in parasites which have lost their plastid due to mis-segregation, indicating that the vesicles are not derived from the apicoplast. To test for a role of the Golgi body in vesicle formation, parasites were treated with brefeldin A or transiently transfected with a dominant-negative mutant of Sar1, a GTPase required for ER to Golgi trafficking. The immunofluorescence patterns showed little change. These findings were confirmed using stable transfectants, which expressed the toxic dominant-negative sar1 following Cre-loxP mediated promoter juxtaposition. Our data support the hypothesis that the large vesicles do not mediate the trafficking of luminal proteins to the apicoplast. The results further show that the large vesicles bearing apicoplast membrane proteins continue to be observed in the absence of Golgi and plastid function. These data raise the possibility that the apicoplast proteome is generated by two novel ER to plastid trafficking pathways, plus the small set of proteins encoded by the apicoplast genome.
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Afanador GA, Matthews KA, Bartee D, Gisselberg JE, Walters MS, Freel Meyers CL, Prigge ST. Redox-dependent lipoylation of mitochondrial proteins in Plasmodium falciparum. Mol Microbiol 2014; 94:156-71. [PMID: 25116855 PMCID: PMC4177315 DOI: 10.1111/mmi.12753] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2014] [Indexed: 11/26/2022]
Abstract
Lipoate scavenging from the human host is essential for malaria parasite survival. Scavenged lipoate is covalently attached to three parasite proteins: the H-protein and the E2 subunits of branched chain amino acid dehydrogenase (BCDH) and α-ketoglutarate dehydrogenase (KDH). We show mitochondrial localization for the E2 subunits of BCDH and KDH, similar to previously localized H-protein, demonstrating that all three lipoylated proteins reside in the parasite mitochondrion. The lipoate ligase 1, LipL1, has been shown to reside in the mitochondrion and it catalyses the lipoylation of the H-protein; however, we show that LipL1 alone cannot lipoylate BCDH or KDH. A second mitochondrial protein with homology to lipoate ligases, LipL2, does not show ligase activity and is not capable of lipoylating any of the mitochondrial substrates. Instead, BCDH and KDH are lipoylated through a novel mechanism requiring both LipL1 and LipL2. This mechanism is sensitive to redox conditions where BCDH and KDH are exclusively lipoylated under strong reducing conditions in contrast to the H-protein which is preferentially lipoylated under less reducing conditions. Thus, malaria parasites contain two different routes of mitochondrial lipoylation, an arrangement that has not been described for any other organism.
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Affiliation(s)
- Gustavo A Afanador
- Department of Molecular Microbiology and Immunology, Johns Hopkins School of Public Health, Baltimore, MD, USA
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Sharma S, Jadli M, Singh A, Arora K, Malhotra P. A secretory multifunctional serine protease, DegP of Plasmodium falciparum, plays an important role in thermo-oxidative stress, parasite growth and development. FEBS J 2014; 281:1679-99. [PMID: 24494818 DOI: 10.1111/febs.12732] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/27/2013] [Accepted: 01/23/2014] [Indexed: 12/12/2022]
Abstract
UNLABELLED Plasmodium falciparum heat shock proteins and proteases are known for their indispensable roles in parasite virulence and survival in the host cell. They neutralize various host-derived stress responses that are deleterious for parasite growth and invasion. We report identification and functional characterization of the first DegP from an apicomplexan (P. falciparum). To determine the molecular identity and functions of the parasite-encoded DegP, we complemented the Escherichia coli degP null mutant with a putative PfdegP gene, and the results showed that PfDegP complements the growth defect of the temperature sensitive DegP-deficient mutant and imparts resistance to non-permissive temperatures and oxidative stress. Molecular interaction studies showed that PfDegP exists as a complex with parasite-encoded heat shock protein 70, iron superoxide dismutase and enolase. DegP expression is significantly induced in parasite culture upon heat shock/oxidative stress. Our data suggest that the PfDegP protein may play a role in the growth and development of P. falciparum through its ability to confer protection against thermal/oxidative stress. Antibody against DegP showed anti-plasmodial activity against blood-stage parasites in vitro, suggesting that PfDegP and its associated complex may be a potential focus for new anti-malarial therapies. STRUCTURED DIGITAL ABSTRACT ●PfDegP physically interacts with PfHsp70 and PfEno by anti-bait co-immunoprecipitation (View interaction) ●PfDegP physically interacts with PfEno, PfSod, PfOat, PfHsp70, PfLDH and PfGpi by anti-bait co-immunoprecipitation (View interaction) ●PfHsp-70 and PfDegP co-localize by fluorescence microscopy (View interaction) ●PfDegP physically interacts with PfOat, PfHsp70, PfEno, PfSod, PfGpi and PfLDH by surface plasmon resonance (View interaction) ●PfEno and PfDegP co-localize by fluorescence microscopy (View interaction) ●PfDegP and PfHsp70 co-localize by co-sedimentation through density gradient (View interaction).
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Affiliation(s)
- Shweta Sharma
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Turturice BA, Lamm MA, Tasch JJ, Zalewski A, Kooistra R, Schroeter EH, Sharma S, Kawazu SI, Kanzok SM. Expression of cytosolic peroxiredoxins in Plasmodium berghei ookinetes is regulated by environmental factors in the mosquito bloodmeal. PLoS Pathog 2013; 9:e1003136. [PMID: 23382676 PMCID: PMC3561267 DOI: 10.1371/journal.ppat.1003136] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Accepted: 11/29/2012] [Indexed: 11/19/2022] Open
Abstract
The Plasmodium ookinete develops over several hours in the bloodmeal of its mosquito vector where it is exposed to exogenous stresses, including cytotoxic reactive oxygen species (ROS). How the parasite adapts to these challenging conditions is not well understood. We have systematically investigated the expression of three cytosolic antioxidant proteins, thioredoxin-1 (Trx-1), peroxiredoxin-1 (TPx-1), and 1-Cys peroxiredoxin (1-Cys Prx), in developing ookinetes of the rodent parasite Plasmodium berghei under various growth conditions. Transcriptional profiling showed that tpx-1 and 1-cys prx but not trx-1 are more strongly upregulated in ookinetes developing in the mosquito bloodmeal when compared to ookinetes growing under culture conditions. Confocal immunofluorescence imaging revealed comparable expression patterns on the corresponding proteins. 1-Cys Prx in particular exhibited strong expression in mosquito-derived ookinetes but was not detectable in cultured ookinetes. Furthermore, ookinetes growing in culture upregulated tpx-1 and 1-cys prx when challenged with exogenous ROS in a dose-dependent fashion. This suggests that environmental factors in the mosquito bloodmeal induce upregulation of cytosolic antioxidant proteins in Plasmodium ookinetes. We found that in a parasite line lacking TPx-1 (TPx-1KO), expression of 1-Cys Prx occurred significantly earlier in mosquito-derived TPx-1KO ookinetes when compared to wild type (WT) ookinetes. The protein was also readily detectable in cultured TPx-1KO ookinetes, indicating that 1-Cys Prx at least in part compensates for the loss of TPx-1 in vivo. We hypothesize that this dynamic expression of the cytosolic peroxiredoxins reflects the capacity of the developing Plasmodium ookinete to rapidly adapt to the changing conditions in the mosquito bloodmeal. This would significantly increase its chances of survival, maturation and subsequent escape. Our results also emphasize that environmental conditions must be taken into account when investigating Plasmodium-mosquito interactions. The malaria parasite Plasmodium is transmitted by Anopheles mosquitoes. Within the midgut of the insect, it is exposed to multiple environmental stresses, including cytotoxic reactive oxygen species (ROS). To avoid destruction, the parasite develops into a motile ookinete capable of leaving the midgut. Yet, ookinete development lasts over several hours and requires the parasite to adapt to an increasingly challenging environment. Here we show that ookinetes of the rodent parasite Plasmodium berghei during development in the mosquito midgut increase the expression of the protective antioxidant proteins peroxiredoxin-1 (TPx-1) and 1-Cys peroxiredoxin (1-Cys Prx). This upregulation was also inducible in cultured ookinetes by challenging them with ROS. This suggests that ookinetes actively modulate the expression of their antioxidant proteins in response to the changing conditions in the mosquito. We also found that ookinetes lacking TPx-1 (TPx-1KO) upregulated 1-Cys Prx expression significantly earlier than wild type ookinetes. This indicates that the TPx-1KO parasites compensate for the loss of TPx-1 by altering the expression pattern of the functionally related 1-Cys Prx. The observed dynamic regulation of the cytosolic antioxidant proteins may help the Plasmodium ookinete to adapt to rapidly changing environmental conditions and thus to increase the probability of survival, maturation and escape from the mosquito midgut.
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Affiliation(s)
- Benjamin A. Turturice
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Michael A. Lamm
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - James J. Tasch
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Angelika Zalewski
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Rachel Kooistra
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Eric H. Schroeter
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Sapna Sharma
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Shin-Ichiro Kawazu
- Obihiro University of Agriculture and Veterinarian Medicine, National Research Center for Protozoan Diseases, Obihiro, Hokkaido, Japan
| | - Stefan M. Kanzok
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- * E-mail:
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