title: SAS6-like protein in Plasmodium indicates that conoid-associated apical complex proteins persist in invasive stages within the mosquito vector.
abstract: The SAS6-like (SAS6L) protein, a truncated paralogue of the ubiquitous basal body/centriole protein SAS6, has been characterised recently as a flagellum protein in trypanosomatids, but associated with the conoid in apicomplexan Toxoplasma. The conoid has been suggested to derive from flagella parts, but is thought to have been lost from some apicomplexans including the malaria-causing genus Plasmodium. Presence of SAS6L in Plasmodium, therefore, suggested a possible role in flagella assembly in male gametes, the only flagellated stage. Here, we have studied the expression and role of SAS6L throughout the Plasmodium life cycle using the rodent malaria model P. berghei. Contrary to a hypothesised role in flagella, SAS6L was absent during gamete flagellum formation. Instead, SAS6L was restricted to the apical complex in ookinetes and sporozoites, the extracellular invasive stages that develop within the mosquito vector. In these stages SAS6L forms an apical ring, as we show is also the case in Toxoplasma tachyzoites. The SAS6L ring was not apparent in blood-stage invasive merozoites, indicating that the apical complex is differentiated between the different invasive forms. Overall this study indicates that a conoid-associated apical complex protein and ring structure is persistent in Plasmodium in a stage-specific manner.
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Wall
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.
authors.forename: Magali
authors.initials: M
authors.lastname: Roques
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|School of Botany, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Katris
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Ludek
authors.initials: L
authors.lastname: Koreny
authors.affiliation: Institute of Cell Biology, University of Bern, CH-3012 Bern, Switzerland.
authors.forename: Rebecca R
authors.initials: RR
authors.lastname: Stanway
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.
authors.forename: Declan
authors.initials: D
authors.lastname: Brady
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Ross F
authors.initials: RF
authors.lastname: Waller
authors.affiliation: School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.
authors.forename: Rita
authors.initials: R
authors.lastname: Tewari
mesh_terms: D000818:Animals; D064652:Basal Bodies / Q000378:metabolism* / Q000469:parasitology; D005260:Female; D005407:Flagella / Q000378:metabolism / Q000469:parasitology; D008018:Life Cycle Stages / Q000502:physiology; D008288:Malaria / Q000378:metabolism / Q000469:parasitology; D052940:Merozoites / Q000378:metabolism; D051379:Mice; D000072138:Mosquito Vectors / Q000378:metabolism* / Q000469:parasitology*; D010961:Plasmodium / Q000378:metabolism* / Q000469:parasitology*; D015800:Protozoan Proteins / Q000378:metabolism*; D034101:Sporozoites / Q000378:metabolism; D014122:Toxoplasma / Q000378:metabolism / Q000469:parasitology
chemical_list: D015800:Protozoan Proteins