Combined Automated Annotation using Multiple IEA Methods
Independent translocation of two micronemal proteins in developing Plasmodium falciparum merozoites.
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Immuno-electron microscopy with a prodomain-specific monoclonal antibody places unprocessed PfAMA1 in the micronemes of intraerythrocytic schizonts, and the mature protein reaches the merozoite surface after prodomain removal.
"We localized unprocessed PfAMA1 to the microneme organelles of the intraerythrocytic schizont."
Plasmodium falciparum AMA1 binds a rhoptry neck protein homologous to TgRON4, a component of the moving junction in Toxoplasma gondii.
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PfAMA1 co-immunoprecipitates with PfRON4, indicating association of AMA1 with the rhoptry neck protein complex in P. falciparum.
"Plasmodium falciparum apical membrane antigen 1 (PfAMA1) coimmunoprecipitates with the Plasmodium homologue of TgRON4, a secreted rhoptry neck protein of Toxoplasma gondii that migrates at the moving junction in association with TgAMA1 during invasion."
Binding of Plasmodium merozoite proteins RON2 and AMA1 triggers commitment to invasion.
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Occupancy of the AMA1 hydrophobic pocket by RON2 is the step at which the merozoite commits to erythrocyte invasion; antibodies to the pocket block junction formation.
"Abs specific for the AMA1 pocket blocked junction formation and the induction of the parasitophorous vacuole."
Structural and functional insights into the malaria parasite moving junction complex.
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Crystal structure of PfAMA1 with a PfRON2 peptide defines the binding site as the hydrophobic groove plus the region exposed by displacement of the domain II loop; point mutations at the interface abolish binding.
"Mutations of key contact residues of PfRON2 and PfAMA1 abrogate binding between the recombinant proteins."
Apical membrane antigen 1 mediates apicomplexan parasite attachment but is dispensable for host cell invasion.
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Zoites lacking AMA1 attach poorly to host cells but penetrate normally once a junction has formed, arguing that AMA1 acts as an adhesin rather than an obligatory invasin.
"Therefore, apical membrane antigen 1, rather than an essential invasin, is a dispensable adhesin of apicomplexan zoites."
Conditional expression of apical membrane antigen 1 in Plasmodium falciparum shows it is required for erythrocyte invasion by merozoites.
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DiCre-mediated excision of Pfama1 reduces the protein by about 80% in one cycle, lowering growth by 40% through reduced invasion efficiency and a defect in sealing the parasitophorous vacuole.
"This reduces growth by 40%, due to decreased invasion efficiency characterized by a post-invasion defect in sealing of the parasitophorous vacuole."
Integral membrane protein located in the apical complex of Plasmodium falciparum.
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Original cloning of the antigen, named for its apparent apical location, with transport to the merozoite surface near schizont rupture.
"Apical membrane antigen 1 appears to be transported to the merozoite surface near the time of schizont rupture."