title: Overall Architecture of the Intraflagellar Transport (IFT)-B Complex Containing Cluap1/IFT38 as an Essential Component of the IFT-B Peripheral Subcomplex.
abstract: Intraflagellar transport (IFT) is essential for assembly and maintenance of cilia and flagella as well as ciliary motility and signaling. IFT is mediated by multisubunit complexes, including IFT-A, IFT-B, and the BBSome, in concert with kinesin and dynein motors. Under high salt conditions, purified IFT-B complex dissociates into a core subcomplex composed of at least nine subunits and at least five peripherally associated proteins. Using the visible immunoprecipitation assay, which we recently developed as a convenient protein-protein interaction assay, we determined the overall architecture of the IFT-B complex, which can be divided into core and peripheral subcomplexes composed of 10 and 6 subunits, respectively. In particular, we identified TTC26/IFT56 and Cluap1/IFT38, neither of which was included with certainty in previous models of the IFT-B complex, as integral components of the core and peripheral subcomplexes, respectively. Consistent with this, a ciliogenesis defect of Cluap1-deficient mouse embryonic fibroblasts was rescued by exogenous expression of wild-type Cluap1 but not by mutant Cluap1 lacking the binding ability to other IFT-B components. The detailed interaction map as well as comparison of subcellular localization of IFT-B components between wild-type and Cluap1-deficient cells provides insights into the functional relevance of the architecture of the IFT-B complex.
authors.affiliation: From the Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Katoh
authors.affiliation: From the Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Terada
authors.affiliation: From the Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Nishijima
authors.affiliation: From the Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Takei
authors.affiliation: From the Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Nozaki
authors.affiliation: the Developmental Genetics Group, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan, and the Center for Developmental Biology, RIKEN, Chuou-ku, Kobe 650-0047, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hamada
authors.affiliation: From the Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, kazunaka@pharm.kyoto-u.ac.jp.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D001692:Biological Transport; D002478:Cells, Cultured; D005407:Flagella / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016547:Kinesins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D060066:Protein Interaction Maps; D021122:Protein Subunits
chemical_list: C583954:Cluap1 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D016547:Kinesins
keywords: Cluap1; IFT-B complex; VIP assay; cell biology; cilia; intracellular trafficking; primary cilium; protein assembly