Localization, biosynthesis, processing and isolation of a major 126 kDa antigen of the parasitophorous vacuole of Plasmodium falciparum

Delplace, Patrick; Fortier, B; Tronchin, G.; Dubremetz, Jean‐François; Vernes, A

doi:10.1016/0166-6851(87)90026-0

Cited by 120 publications

(71 citation statements)

References 16 publications

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“…This excludes that the presence of REX3 in the clefts lumen. When we analyzed the PV soluble protein SERP ( Delplace et al, 1987), we noticed that the PVM was partly breached under these SLO concentrations, as apparent from the release of some of this protein into the supernatant ( Figure 6C). However, although treatment of the SLO pellet with saponin released the remaining SERP, no REX3 was released.…”

Section: Rex3 Is a Soluble Protein Exported Into The Host Cell Cytoplasmmentioning

confidence: 99%

A Cluster of Ring Stage–specific Genes Linked to a Locus Implicated in Cytoadherence inPlasmodium falciparumCodes for PEXEL-negative and PEXEL-positive Proteins Exported into the Host Cell

Spielmann

Hawthorne

Dixon

et al. 2006

MBoC

116

162

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Blood stages of Plasmodium falciparum export proteins into their erythrocyte host, thereby inducing extensive host cell modifications that become apparent after the first half of the asexual development cycle (ring stage). This is responsible for a major part of parasite virulence. Export of many parasite proteins depends on a sequence motif termed Plasmodium export element (PEXEL) or vacuolar transport signal (VTS). This motif has allowed the prediction of the Plasmodium exportome. Using published genome sequence, we redetermined the boundaries of a previously studied region linked to P. falciparum virulence, reducing the number of candidate genes in this region to 13. Among these, we identified a cluster of four ring stage-specific genes, one of which is known to encode an exported protein. We demonstrate that all four genes code for proteins exported into the host cell, although only two genes contain an obvious PEXEL/VTS motif. We propose that the systematic analysis of ring stage-specific genes will reveal a cohort of exported proteins not present in the currently predicted exportome. Moreover, this provides further evidence that host cell remodeling is a major task of this developmental stage. Biochemical and photobleaching studies using these proteins reveal new properties of the parasiteinduced membrane compartments in the host cell. This has important implications for the biogenesis and connectivity of these structures. INTRODUCTIONPlasmodium falciparum is the causative agent of the most severe form of human malaria, killing 1-2 million people each year (Snow et al., 2005). The symptoms of this disease are associated with the continuous asexual multiplication of P. falciparum parasites within red blood cells (RBCs) (for review, see Miller et al., 2002). In this part of the life cycle, the parasite develops, within 48 h from the ring stage, to the trophozoite stage and finally to the schizont stage after which the infected RBCs (IRBCs) rupture, releasing up to 32 merozoite stage parasites that infect new RBCs.The ring stage lasts for almost half of this cycle (ϳ0-20 h after invasion) and shows low metabolic activity with little change in size and morphology (Zolg et al., 1984;de Rojas and Wasserman, 1985). P. falciparum ring forms are the only stages apparent in the blood circulation of infected humans, because more mature parasites adhere to the endothelium of various organs to avoid clearance by the spleen (Langreth and Peterson, 1985). The subsequent accumulation of infected RBCs in the microvasculature is largely responsible for malaria-associated morbidity and mortality. This sequestration of IRBCs is mediated by the parasite protein P. falciparum erythrocyte membrane protein 1 (PfEMP-1), which is exported to the surface of the IRBCs and is encoded by a family of variant antigens (Baruch et al., 1995;Smith et al., 1995;Su et al., 1995). Because human RBCs are devoid of a functional protein trafficking system, the parasite has to establish a protein export system in the host cell before PfEMP-1 can b...

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Section: Rex3 Is a Soluble Protein Exported Into The Host Cell Cytoplasmmentioning

confidence: 99%

A Cluster of Ring Stage–specific Genes Linked to a Locus Implicated in Cytoadherence inPlasmodium falciparumCodes for PEXEL-negative and PEXEL-positive Proteins Exported into the Host Cell

Spielmann

Hawthorne

Dixon

et al. 2006

MBoC

116

162

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“…1 also known as serine stretch protein (SERP) or P126 (1)(2)(3). SERA, which is produced in large amounts late in the blood stage cycle, is the target of protective immune responses and possesses a domain that may function as a protease (4 -10).…”

mentioning

confidence: 99%

“…falciparum SERA/SERP is synthesized as a 113-126-kDa precursor protein and is localized to the parasitophorous vacuole (1,2,11). Synchronous with merozoite release, the precursor is processed into N-terminal 47-kDa, centrally located 56-kDa, and C-terminal 18-kDa fragments.…”

mentioning

confidence: 99%

A Subset of Plasmodium falciparum SERA Genes Are Expressed and Appear to Play an Important Role in the Erythrocytic Cycle

Miller¹,

Good

Drew³

et al. 2002

Journal of Biological Chemistry

160

173

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The Plasmodium falciparum serine repeat antigen (SERA) has shown considerable promise as a blood stage vaccine for the control of malaria. A related protein, SERPH, has also been described in P. falciparum. Whereas their biological role remains unknown, both proteins possess papain-like protease domains that may provide attractive targets for therapeutic intervention. Genomic sequencing has recently shown that SERA and SERPH are the fifth and sixth genes, respectively, in a cluster of eight SERA homologues present on chromosome 2. In this paper, the expression and functional relevance of these eight genes and of a ninth SERA homologue found on chromosome 9 were examined in blood stage parasites. Using reverse transcriptase-PCR and microarray approaches, we demonstrate that whereas mRNA to all nine SERA genes is synthesized late in the erythrocytic cycle, it is those genes in the central region of the chromosome 2 cluster that are substantially up-regulated at this time. Using antibodies specific to each SERA, it was apparent that SERA4 to -6, and possibly also SERA9, are synthesized in blood stage parasites. The reactivity of antibodies from malaria-immune individuals with the SERA recombinant proteins suggested that SERA2 and SERA3 are also expressed at least in some parasite populations. To examine whether SERA genes are essential to blood stage growth, each of the eight chromosome 2 SERA genes was targeted for disruption. Whereas genes at the periphery of the cluster were mostly dispensable (SERA2 and -3 and SERA7 and -8), those in the central region (SERA4 to -6) could not be disrupted. The inability to disrupt SERA4, -5, and -6 is consistent with their apparent dominant expression and implies an important role for these genes in maintenance of the erythrocytic cycle.

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“…Because SERA and its homologues contain an approximately 30-kDa protease domain with similarity to papain-like cysteine proteases and some are known to be expressed in late schizonts, they have been implicated in events of rupture or invasion as well. Interestingly, P126 (SERA) has been shown to be a major component of the parasitophorous vacuole in late erythrocytic stages and is proteolytically processed upon release of merozoites into culture mediumprocessing that is altered with the addition of the protease inhibitor leupeptin (4,9,10). The aspartic protease plasmepsin II has also been shown to be secreted to the parasite periphery in late schizonts and is active in degrading spectrin (11).…”

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confidence: 99%

From the Cover: Malaria parasite exit from the host erythrocyte: A two-step process requiring extraerythrocytic proteolysis

Salmon¹

2000

Proceedings of the National Academy of Sciences

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Intraerythrocytic malaria parasites replicate by the process of schizogeny, during which time they copy their genetic material and package it into infective merozoites. These merozoites must then exit the host cell to invade new erythrocytes. To better characterize the events of merozoite escape, erythrocytes containing Plasmodium falciparum schizonts were cultured in the presence of the cysteine protease inhibitor, L-transepoxy-succinyl-leucylamido-(4-guanidino)butane (E64). This treatment resulted in the accumulation of extraerythrocytic merozoites locked within a thin, transparent membrane. Immunomicroscopy demonstrated that the single membrane surrounding the merozoites is not erythrocytic but rather is derived from the parasitophorous vacuolar membrane (PVM). Importantly, structures identical in appearance can be detected in untreated cultures at low frequency. Further studies revealed that (i) merozoites from the PVM-enclosed merozoite structures (PEMS) are invasive, viable, and capable of normal development; (ii) PEMS can be purified easily and efficiently; and (iii) when PEMS are added to uninfected red blood cells, released merozoites can establish a synchronous wave of infection. These observations suggest that L-transepoxy-succinyl-leucylamido-(4-guanidino)butane (E64) causes an accumulation of an intermediate normally present during the process of rupture. We propose a model for the process of rupture: merozoites enclosed within the PVM first exit from the host erythrocyte and then rapidly escape from the PVM by a proteolysis-dependent mechanism.M alaria afflicts an estimated 300 million to 500 million people and is responsible for the death of nearly 2 million children each year (1). Malaria is caused by several species of obligate intracellular protozoan parasites, the most deadly of which is Plasmodium falciparum. The malaria parasite completes its asexual life cycle in the mature human erythrocyte within a vacuole, delimited by the parasitophorous vacuole membrane (PVM). While in the red cell, the parasite undergoes three distinct stages of development: the ring, the trophozoite, and the schizont stage. During schizony, the parasite divides within the vacuole to form between 16 and 32 merozoites. Approximately 48 h after infection, the merozoites rupture from within the red cell to invade new cells and continue the cycle.In a 1986 study by Lyon and Haynes (2), purified P. falciparum schizonts that were cultured in the presence of small concentrations of leupeptin and chymostatin failed to properly rupture and, instead, formed ''protease inhibitor clusters of merozoites.'' A number of proteases are suspected to be involved in parasite exit, based on circumstantial evidence. The stage-specific expression of a cysteine protease (35,000-40,000 M r ) and a serine protease (75,000 M r ) found in mature schizonts and merozoites, respectively, implicates them in the process of rupture or invasion (3). The P. falciparum serine repeat antigen, known as SERA, P126, SERA-1, and SERP, is one of several homolo...

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Localization, biosynthesis, processing and isolation of a major 126 kDa antigen of the parasitophorous vacuole of Plasmodium falciparum

Cited by 120 publications

References 16 publications

A Cluster of Ring Stage–specific Genes Linked to a Locus Implicated in Cytoadherence inPlasmodium falciparumCodes for PEXEL-negative and PEXEL-positive Proteins Exported into the Host Cell

A Cluster of Ring Stage–specific Genes Linked to a Locus Implicated in Cytoadherence inPlasmodium falciparumCodes for PEXEL-negative and PEXEL-positive Proteins Exported into the Host Cell

A Subset of Plasmodium falciparum SERA Genes Are Expressed and Appear to Play an Important Role in the Erythrocytic Cycle

From the Cover: Malaria parasite exit from the host erythrocyte: A two-step process requiring extraerythrocytic proteolysis

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