title: A MAP6-related protein is present in protozoa and is involved in flagellum motility.
abstract: In vertebrates the microtubule-associated proteins MAP6 and MAP6d1 stabilize cold-resistant microtubules. Cilia and flagella have cold-stable microtubules but MAP6 proteins have not been identified in these organelles. Here, we describe TbSAXO as the first MAP6-related protein to be identified in a protozoan, Trypanosoma brucei. Using a heterologous expression system, we show that TbSAXO is a microtubule stabilizing protein. Furthermore we identify the domains of the protein responsible for microtubule binding and stabilizing and show that they share homologies with the microtubule-stabilizing Mn domains of the MAP6 proteins. We demonstrate, in the flagellated parasite, that TbSAXO is an axonemal protein that plays a role in flagellum motility. Lastly we provide evidence that TbSAXO belongs to a group of MAP6-related proteins (SAXO proteins) present only in ciliated or flagellated organisms ranging from protozoa to mammals. We discuss the potential roles of the SAXO proteins in cilia and flagella function.
authors.affiliation: Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Dacheux
authors.forename: Nicolas
authors.initials: N
authors.lastname: Landrein
authors.forename: Magali
authors.initials: M
authors.lastname: Thonnus
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gilbert
authors.forename: Annelise
authors.initials: A
authors.lastname: Sahin
authors.forename: Harald
authors.initials: H
authors.lastname: Wodrich
authors.forename: Derrick R
authors.initials: DR
authors.lastname: Robinson
authors.forename: Mélanie
authors.initials: M
authors.lastname: Bonhivers
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002465:Cell Movement / Q000502:physiology*; D002923:Cilia / Q000378:metabolism; D005407:Flagella / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D015388:Organelles / Q000378:metabolism; D011485:Protein Binding; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism*; D014353:Trypanosomiasis, African / Q000235:genetics / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D015800:Protozoan Proteins