title: Ciliary entry of KIF17 is dependent on its binding to the IFT-B complex via IFT46-IFT56 as well as on its nuclear localization signal.
abstract: Cilia function as cellular antennae to sense and transduce extracellular signals. A number of proteins are specifically localized in cilia. Anterograde and retrograde ciliary protein trafficking are mediated by the IFT-B and IFT-A complexes in concert with kinesin-2 and dynein-2 motors, respectively. However, the role of KIF17, a homodimeric kinesin-2 protein, in protein trafficking has not been fully understood in vertebrate cilia. In this study, we demonstrated, by using the visible immunoprecipitation assay, that KIF17 interacts with the IFT46-IFT56 dimer in the IFT-B complex through its C-terminal sequence located immediately upstream of the nuclear localization signal (NLS). We then showed that KIF17 reaches the ciliary tip independently of its motor domain and requires IFT-B binding for its entry into cilia rather than for its intraciliary trafficking. We further showed that KIF17 ciliary entry depends not only on its binding to IFT-B but also on its NLS, to which importin α proteins bind. Taking the results together, we conclude that in mammalian cells, KIF17 is dispensable for ciliogenesis and IFT-B trafficking but requires IFT-B, as well as its NLS, for its ciliary entry across the permeability barrier located at the ciliary base.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Teruki
authors.initials: T
authors.lastname: Funabashi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Katoh
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Michisaka
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Terada
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Maho
authors.initials: M
authors.lastname: Sugawa
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan kazunaka@pharm.kyoto-u.ac.jp.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D054468:Axoneme / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002923:Cilia / Q000378:metabolism*; D004398:Dyneins / Q000378:metabolism; D005407:Flagella / Q000378:metabolism; D055786:Gene Knockout Techniques; D006801:Humans; D016547:Kinesins / Q000378:metabolism*; D020409:Molecular Motor Proteins / Q000378:metabolism*; D019913:Nuclear Localization Signals / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C485813:KIF17 protein, human; C509805:KIF2A protein, human; D020409:Molecular Motor Proteins; D019913:Nuclear Localization Signals; D004398:Dyneins; D016547:Kinesins