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The cytoplasmic domain of the Plasmodium falciparum ligand EBA-175 is essential for invasion but not protein trafficking.

Gilberger TW, Thompson JK, Reed MB, Good RT, Cowman AF - J. Cell Biol. (2003)

Bottom Line: The invasion of host cells by the malaria parasite Plasmodium falciparum requires specific protein-protein interactions between parasite and host receptors and an intracellular translocation machinery to power the process.In this report, we show that the cytoplasmic domain of EBA-175 encodes crucial information for its role in merozoite invasion, and that trafficking of this protein is independent of this domain.These results show that the parasite uses the same components of its cellular machinery for invasion regardless of the host cell type and invasive form.

View Article: PubMed Central - PubMed

Affiliation: The Walter and Eliza Hall Institute of Medical Research, Melbourne 3050, Australia.

ABSTRACT
The invasion of host cells by the malaria parasite Plasmodium falciparum requires specific protein-protein interactions between parasite and host receptors and an intracellular translocation machinery to power the process. The transmembrane erythrocyte binding protein-175 (EBA-175) and thrombospondin-related anonymous protein (TRAP) play central roles in this process. EBA-175 binds to glycophorin A on human erythrocytes during the invasion process, linking the parasite to the surface of the host cell. In this report, we show that the cytoplasmic domain of EBA-175 encodes crucial information for its role in merozoite invasion, and that trafficking of this protein is independent of this domain. Further, we show that the cytoplasmic domain of TRAP, a protein that is not expressed in merozoites but is essential for invasion of liver cells by the sporozoite stage, can substitute for the cytoplasmic domain of EBA-175. These results show that the parasite uses the same components of its cellular machinery for invasion regardless of the host cell type and invasive form.

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Expression and localization of EBA-175TRAP in transgenic parasites. Immunofluorescence assays using anti-TRAP-CT, anti-EBA-175 and anti-EBA-181 antibodies with parasite lines W2mef and W2mefTRAP are shown. Structural features of EBA-175 compared with the chimeric protein EBA-175TRAP. Nuclei are stained with DAPI in the first panel of each row. EBA-175 colocalizes with the microneme protein EBA-181 in W2mef parasites. EBA-175TRAP is not expressed in W2mef parasites but is expressed in W2mefTRAP transgenic parasites. It colocalizes with the micronemal protein EBA-181. The EBA-175 and EBA-181 patterns are merged to show colocalization in the last panel of each row.
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fig5: Expression and localization of EBA-175TRAP in transgenic parasites. Immunofluorescence assays using anti-TRAP-CT, anti-EBA-175 and anti-EBA-181 antibodies with parasite lines W2mef and W2mefTRAP are shown. Structural features of EBA-175 compared with the chimeric protein EBA-175TRAP. Nuclei are stained with DAPI in the first panel of each row. EBA-175 colocalizes with the microneme protein EBA-181 in W2mef parasites. EBA-175TRAP is not expressed in W2mef parasites but is expressed in W2mefTRAP transgenic parasites. It colocalizes with the micronemal protein EBA-181. The EBA-175 and EBA-181 patterns are merged to show colocalization in the last panel of each row.

Mentions: EBA-175 functions in merozoite invasion of erythrocytes (Sim et al., 1994; Reed et al., 2000a), whereas TRAP is required for invasion of sporozoites into liver cells (Sultan et al., 1997). To test if the cytoplasmic tail of the TRAP protein was able to substitute for the same region in EBA-175, we replaced the COOH-terminal 54 amino acids with the last 37 amino acids of TRAP (Fig. 1 B). As expected, no fluorescence was detectable with anti-TRAP antibodies in W2mef. However, anti-TRAP-CT detected the EBA-175TRAP chimeric protein in W2mefTRAP parasites, and this protein showed colocalization with the micronemal marker EBA-181 in schizonts and merozoites (Fig. 3 and Fig. 5).


The cytoplasmic domain of the Plasmodium falciparum ligand EBA-175 is essential for invasion but not protein trafficking.

Gilberger TW, Thompson JK, Reed MB, Good RT, Cowman AF - J. Cell Biol. (2003)

Expression and localization of EBA-175TRAP in transgenic parasites. Immunofluorescence assays using anti-TRAP-CT, anti-EBA-175 and anti-EBA-181 antibodies with parasite lines W2mef and W2mefTRAP are shown. Structural features of EBA-175 compared with the chimeric protein EBA-175TRAP. Nuclei are stained with DAPI in the first panel of each row. EBA-175 colocalizes with the microneme protein EBA-181 in W2mef parasites. EBA-175TRAP is not expressed in W2mef parasites but is expressed in W2mefTRAP transgenic parasites. It colocalizes with the micronemal protein EBA-181. The EBA-175 and EBA-181 patterns are merged to show colocalization in the last panel of each row.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2172798&req=5

fig5: Expression and localization of EBA-175TRAP in transgenic parasites. Immunofluorescence assays using anti-TRAP-CT, anti-EBA-175 and anti-EBA-181 antibodies with parasite lines W2mef and W2mefTRAP are shown. Structural features of EBA-175 compared with the chimeric protein EBA-175TRAP. Nuclei are stained with DAPI in the first panel of each row. EBA-175 colocalizes with the microneme protein EBA-181 in W2mef parasites. EBA-175TRAP is not expressed in W2mef parasites but is expressed in W2mefTRAP transgenic parasites. It colocalizes with the micronemal protein EBA-181. The EBA-175 and EBA-181 patterns are merged to show colocalization in the last panel of each row.
Mentions: EBA-175 functions in merozoite invasion of erythrocytes (Sim et al., 1994; Reed et al., 2000a), whereas TRAP is required for invasion of sporozoites into liver cells (Sultan et al., 1997). To test if the cytoplasmic tail of the TRAP protein was able to substitute for the same region in EBA-175, we replaced the COOH-terminal 54 amino acids with the last 37 amino acids of TRAP (Fig. 1 B). As expected, no fluorescence was detectable with anti-TRAP antibodies in W2mef. However, anti-TRAP-CT detected the EBA-175TRAP chimeric protein in W2mefTRAP parasites, and this protein showed colocalization with the micronemal marker EBA-181 in schizonts and merozoites (Fig. 3 and Fig. 5).

Bottom Line: The invasion of host cells by the malaria parasite Plasmodium falciparum requires specific protein-protein interactions between parasite and host receptors and an intracellular translocation machinery to power the process.In this report, we show that the cytoplasmic domain of EBA-175 encodes crucial information for its role in merozoite invasion, and that trafficking of this protein is independent of this domain.These results show that the parasite uses the same components of its cellular machinery for invasion regardless of the host cell type and invasive form.

View Article: PubMed Central - PubMed

Affiliation: The Walter and Eliza Hall Institute of Medical Research, Melbourne 3050, Australia.

ABSTRACT
The invasion of host cells by the malaria parasite Plasmodium falciparum requires specific protein-protein interactions between parasite and host receptors and an intracellular translocation machinery to power the process. The transmembrane erythrocyte binding protein-175 (EBA-175) and thrombospondin-related anonymous protein (TRAP) play central roles in this process. EBA-175 binds to glycophorin A on human erythrocytes during the invasion process, linking the parasite to the surface of the host cell. In this report, we show that the cytoplasmic domain of EBA-175 encodes crucial information for its role in merozoite invasion, and that trafficking of this protein is independent of this domain. Further, we show that the cytoplasmic domain of TRAP, a protein that is not expressed in merozoites but is essential for invasion of liver cells by the sporozoite stage, can substitute for the cytoplasmic domain of EBA-175. These results show that the parasite uses the same components of its cellular machinery for invasion regardless of the host cell type and invasive form.

Show MeSH
Related in: MedlinePlus