title: Host cell entry by apicomplexa parasites requires actin polymerization in the host cell.
abstract: Apicomplexa are obligate intracellular parasites that actively invade host cells using their membrane-associated, actin-myosin motor. The current view is that host cell invasion by Apicomplexa requires the formation of a parasite-host cell junction, which has been termed the moving junction, but does not require the active participation of host actin. Using Toxoplasma gondii tachyzoites and Plasmodium berghei sporozoites, we show that host actin participates in parasite entry. Parasites induce the formation of a ring-shaped F-actin structure in the host cell at the parasite-cell junction, which remains stable during parasite entry. The Arp2/3 complex, an actin-nucleating factor, is recruited at the ring structure and is important for parasite entry. We propose that Apicomplexa invasion of host cells requires not only the parasite motor but also de novo polymerization of host actin at the entry site for anchoring the junction on which the parasite pulls to penetrate the host cell.
authors.affiliation: Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Gonzalez
authors.forename: Audrey
authors.initials: A
authors.lastname: Combe
authors.forename: Violaine
authors.initials: V
authors.lastname: David
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Malmquist
authors.forename: Violaine
authors.initials: V
authors.lastname: Delorme
authors.forename: Carole
authors.initials: C
authors.lastname: Leroy
authors.forename: Samantha
authors.initials: S
authors.lastname: Blazquez
authors.forename: Robert
authors.initials: R
authors.lastname: Ménard
authors.forename: Isabelle
authors.initials: I
authors.lastname: Tardieux
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000032:analysis; D000199:Actins / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D003593:Cytoplasm / Q000737:chemistry; D006790:Host-Parasite Interactions; D006801:Humans; D010962:Plasmodium berghei / Q000502:physiology*; D055503:Protein Multimerization; D014122:Toxoplasma / Q000502:physiology*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins