title: Independent roles of apical membrane antigen 1 and rhoptry neck proteins during host cell invasion by apicomplexa.
abstract: During invasion, apicomplexan parasites form an intimate circumferential contact with the host cell, the tight junction (TJ), through which they actively glide. The TJ, which links the parasite motor to the host cell cytoskeleton, is thought to be composed of interacting apical membrane antigen 1 (AMA1) and rhoptry neck (RON) proteins. Here we find that, in Plasmodium berghei, while both AMA1 and RON4 are important for merozoite invasion of erythrocytes, only RON4 is required for sporozoite invasion of hepatocytes, indicating that RON4 acts independently of AMA1 in the sporozoite. Further, in the Toxoplasma gondii tachyzoite, AMA1 is dispensable for normal RON4 ring and functional TJ assembly but enhances tachyzoite apposition to the cell and internalization frequency. We propose that while the RON proteins act at the TJ, AMA1 mainly functions on the zoite surface to permit correct attachment to the cell, which may facilitate invasion depending on the zoite-cell combination.
authors.affiliation: Institut Pasteur, Unité de Biologie et Génétique du Paludisme, 75724 Paris, France.
authors.forename: Donatella
authors.initials: D
authors.lastname: Giovannini
authors.forename: Stephan
authors.initials: S
authors.lastname: Späth
authors.forename: Céline
authors.initials: C
authors.lastname: Lacroix
authors.forename: Audrey
authors.initials: A
authors.lastname: Perazzi
authors.forename: Daniel
authors.initials: D
authors.lastname: Bargieri
authors.forename: Vanessa
authors.initials: V
authors.lastname: Lagal
authors.forename: Camille
authors.initials: C
authors.lastname: Lebugle
authors.forename: Audrey
authors.initials: A
authors.lastname: Combe
authors.forename: Sabine
authors.initials: S
authors.lastname: Thiberge
authors.forename: Patricia
authors.initials: P
authors.lastname: Baldacci
authors.forename: Isabelle
authors.initials: I
authors.lastname: Tardieux
authors.forename: Robert
authors.initials: R
authors.lastname: Ménard
mesh_terms: D000818:Animals; D000852:Anopheles; D000953:Antigens, Protozoan / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004912:Erythrocytes / Q000469:parasitology; D022781:Hepatocytes / Q000469:parasitology; D006790:Host-Parasite Interactions; D006801:Humans; D008288:Malaria / Q000469:parasitology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010962:Plasmodium berghei / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D034101:Sporozoites / Q000378:metabolism; D014122:Toxoplasma / Q000235:genetics / Q000378:metabolism*
chemical_list: D000953:Antigens, Protozoan; D008565:Membrane Proteins; D015800:Protozoan Proteins; C090077:apical membrane antigen I, Plasmodium