title: Structural basis of outer dynein arm intraflagellar transport by the transport adaptor protein ODA16 and the intraflagellar transport protein IFT46.
abstract: Motile cilia are found on unicellular organisms such as the green algaChlamydomonas reinhardtii, on sperm cells, and on cells that line the trachea and fallopian tubes in mammals. The motility of cilia relies on a number of large protein complexes including the force-generating outer dynein arms (ODAs). The transport of ODAs into cilia has been previously shown to require the transport adaptor ODA16, as well as the intraflagellar transport (IFT) protein IFT46, but the molecular mechanism by which ODAs are recognized and transported into motile cilia is still unclear. Here, we determined the high-resolution crystal structure ofC. reinhardtiiODA16 (CrODA16) and mapped the binding to IFT46 and ODAs. The CrODA16 structure revealed a small 80-residue N-terminal domain and a C-terminal 8-bladed β-propeller domain that are both required for the association with the N-terminal 147 residues of IFT46. The dissociation constant of the IFT46-ODA16 complex was 200 nm, demonstrating that CrODA16 associates with the IFT complex with an affinity comparable with that of the individual IFT subunits. Furthermore, we show, using ODAs extracted from the axonemes ofC. reinhardtii, that the C-terminal β-propeller but not the N-terminal domain of CrODA16 is required for the interaction with ODAs. These data allowed us to present an architectural model for ODA16-mediated IFT of ODAs.
authors.affiliation: From the Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Taschner
authors.affiliation: the Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Mourão
authors.affiliation: the Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, and.
authors.forename: Mayanka
authors.initials: M
authors.lastname: Awasthi
authors.affiliation: the Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, D-82152 Martinsried, Germany.
authors.forename: Jerome
authors.initials: J
authors.lastname: Basquin
authors.affiliation: From the Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark, el@mbg.au.dk.
authors.forename: Esben
authors.initials: E
authors.lastname: Lorentzen
mesh_terms: D054468:Axoneme / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004398:Dyneins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005407:Flagella / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D021381:Protein Transport / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D010940:Plant Proteins; D004398:Dyneins
keywords: IFT; adaptor protein; cilium; crystal structure; dynein; flagellum; intracellular trafficking; intraflagellar transport; outer dynein arms; primary cilium