title: Critical role for a stage-specific actin in male exflagellation of the malaria parasite.
abstract: Male gametogenesis occurs directly after uptake of malaria parasites by the mosquito vector and leads to the release of eight nucleated flagellar gametes. Here, we report that one of the two parasite actin isoforms, named actin II, is essential for this process. Disruption of actin II in Plasmodium berghei resulted in viable asexual blood stages, but male gametogenesis was specifically inhibited. Upon activation, male gametocyte DNA was replicated normally and axonemes assembled, but egress from the host cell was inhibited, and axoneme motility abolished. The major actin isoform, actin I, displayed dual localization to the cytoplasm and the nucleus in male gametocytes. After activation actin I was found to be restricted to the cytoplasm. In actII(-) mutant parasites, this re-localization was abolished and actin I remained in both cellular compartments. These findings reveal vital and pleiotropic functions for the actin II isoform in male gametogenesis of the malaria parasite.
authors.affiliation: Institute of Molecular Biology and Biotechnology, FORTH, Heraklion, Greece.
authors.forename: Elena
authors.initials: E
authors.lastname: Deligianni
authors.forename: Rhiannon N
authors.initials: RN
authors.lastname: Morgan
authors.forename: Lucia
authors.initials: L
authors.lastname: Bertuccini
authors.forename: Taco W A
authors.initials: TW
authors.lastname: Kooij
authors.forename: Alice
authors.initials: A
authors.lastname: Laforge
authors.forename: Carolin
authors.initials: C
authors.lastname: Nahar
authors.forename: Nikos
authors.initials: N
authors.lastname: Poulakakis
authors.forename: Herwig
authors.initials: H
authors.lastname: Schüler
authors.forename: Christos
authors.initials: C
authors.lastname: Louis
authors.forename: Kai
authors.initials: K
authors.lastname: Matuschewski
authors.forename: Inga
authors.initials: I
authors.lastname: Siden-Kiamos
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry; D016000:Cluster Analysis; D009033:Culicidae / Q000469:parasitology; D003593:Cytoplasm / Q000737:chemistry; D005407:Flagella / Q000502:physiology*; D055786:Gene Knockout Techniques; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010802:Phylogeny; D010962:Plasmodium berghei / Q000502:physiology*; D017386:Sequence Homology, Amino Acid
chemical_list: D000199:Actins