Article

A Central Role for P48/45 in Malaria Parasite Male Gamete Fertility

Leiden University, Leyden, South Holland, Netherlands
Cell (Impact Factor: 32.24). 02/2001; 104(1):153-64. DOI: 10.1016/S0092-8674(01)00199-4
Source: PubMed

ABSTRACT

Fertilization and zygote development are obligate features of the malaria parasite life cycle and occur during parasite transmission to mosquitoes. The surface protein PFS48/45 is expressed by male and female gametes of Plasmodium falciparum and PFS48/45 antibodies prevent zygote development and transmission. Here, gene disruption was used to show that Pfs48/45 and the ortholog Pbs48/45 from a rodent malaria parasite P. berghei play a conserved and important role in fertilization. p48/45- parasites had a reduced capacity to produce oocysts in mosquitoes due to greatly reduced zygote formation. Unexpectedly, only male gamete fertility of p48/45- parasites was affected, failing to penetrate otherwise fertile female gametes. P48/45 is shown to be a surface protein of malaria parasites with a demonstrable role in fertilization.

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Available from: Joanna A M Braks, Mar 10, 2015
    • "These events result in an increased binding of the PfCCp-based MPC to the PPM of gametocytes, probably promoting its stability and its linkage to the parasite surface, once the parasitophorous vacuole dissolves and the gametes emerge from the enveloping red blood cell (Fig. 2B). All of the MPC components have previously been linked to parasite reproduction and further development in the mosquito midgut [4] [8] [9] [17] [18]. In view of the available data on the MPC components we hypothesize that Pfs230 plays an essential role in linking the MPC to the PPM. "
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    ABSTRACT: During differentiation in the human, the gametocytes of the malaria parasite Plasmodium falciparum display a remarkable number of adhesive proteins on their plasma membrane. These include the PfCCp protein family of six secreted proteins that assemble to multimeric protein complexes (MPCs) within the gametocyte parasitophorous vacuole. We now show that the PfCCp-based MPCs are linked to the gametocyte plasma membrane via interactionswith Pfs230, a binding-partner of the GPI-anchored Pfs48/45. Upon onset of gametogenesis, which takes place after gametocyte uptake by blood-feeding mosquitoes, GPI-anchored Pfs25 joins the MPC, providing an additional link of its components to the plasma membrane. Gametogenesis also initiates cleavage of Pfs230 at its N-terminal site, resulting in its increased interaction with the MPC. Either lack of Pfs230 or impaired Pfs230 processing causes proteolysis of the PfCCp proteins and release from the MPC. Our data point to MPC assembly as a crucial step for sexual reproduction.
    No preview · Article · Sep 2015 · Parasitology International
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    • "Once inside the mosquito midgut the parasite emerges from the erythrocyte as a gamete, exposing Pfs48/45 on the surface where it can be targeted by antibodies and other components of the blood meal [4]. The cellular localization and the critical role of Pfs48/45 for male gamete fertility [8] make Pfs48/45 a lead candidate for clinical vaccine development. Pfs48/45 in general and the C-terminal portion in particular is relatively cysteine-rich with multiple disulfide bonds resulting in "
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    ABSTRACT: The sexual stage Pfs48/45 antigen is a well-established lead candidate for a transmission blocking (TB) vaccine because of its critical role in parasite fertilization. We have recently produced the carboxy-terminal 10C-fragment of Pfs48/45 containing three known epitopes for TB antibodies as a chimera with the N-terminal region of GLURP (R0). The resulting fusion protein elicited high titer TB antibodies in rodents. To increase the relatively low yield of correctly folded Pfs48/45 we have generated a series of novel chimera truncating the 10C-fragments to 6 cysteine residues containing sub-units (6C). All constructs harbor the major epitope I for TB antibodies. One of these sub-units (R0.6Cc), produced high yields of correctly folded conformers, which could be purified by a simple 2-step procedure. Purified R0.6Cc was stable and elicits high titer TB antibodies in rats. The yield, purity and stability of R0.6Cc allows for further clinical development. Copyright © 2015. Published by Elsevier Ltd.
    Full-text · Article · Feb 2015 · Vaccine
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    • "So far, we determined a ∼ 10-fold reduction in microgamete formation, yet observed a ∼ 100-fold reduced oocyst burden in cutp− parasites. To confirm a male fertility defect and test female fertility, we performed a cross-fertilization assay and quantified the resulting ookinetes, a functional read-out for gamete fertility (van Dijk et al., 2001; 2010,). As published previously, no ookinetes were detectable in cultures containing p48/45− or p47− parasites alone, whereas in co-cultures p47− male microgametes were able to productively fertilize p48/45− females and ookinetes were readily formed (Fig. 7). "
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    ABSTRACT: Homeostasis of the trace element copper is essential to all eukaryotic life. Copper serves as a cofactor in metalloenzymes and catalyzes electron transfer reactions as well as the generation of potentially toxic reactive oxygen species. Here, we describe the functional characterization of an evolutionarily highly conserved, predicted copper-transporting P-type ATPase (CuTP) in the murine malaria model parasite Plasmodium berghei. Live imaging of a parasite line expressing a fluorescently tagged CuTP demonstrated that CuTP is predominantly located in vesicular bodies of the parasite. A P. berghei loss-of-function mutant line was readily obtained and showed no apparent defect in in vivo blood stage growth. Parasite transmission through the mosquito vector was severely affected, but not entirely abolished. We show that male and female gametocytes are abundant in cutp(-) parasites, but activation of male microgametes and exflagellation were strongly impaired. This specific defect could be mimicked by addition of the copper chelator neocuproine to wild-type gametocytes. A cross-fertilization assay demonstrated that female fertility was also severely abrogated. In conclusion, we provide experimental genetic and pharmacological evidence that a healthy copper homeostasis is critical to malaria parasite fertility of both genders of gametocyte and, hence, to transmission to the mosquito vector.
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