title: Regulation of ciliary retrograde protein trafficking by the Joubert syndrome proteins ARL13B and INPP5E.
abstract: ARL13B (a small GTPase) and INPP5E (a phosphoinositide 5-phosphatase) are ciliary proteins encoded by causative genes of Joubert syndrome. We here showed, by taking advantage of a visible immunoprecipitation assay, that ARL13B interacts with the IFT46 -: IFT56 (IFT56 is also known as TTC26) dimer of the intraflagellar transport (IFT)-B complex, which mediates anterograde ciliary protein trafficking. However, the ciliary localization of ARL13B was found to be independent of its interaction with IFT-B, but dependent on the ciliary-targeting sequence RVEP in its C-terminal region. ARL13B-knockout cells had shorter cilia than control cells and exhibited aberrant localization of ciliary proteins, including INPP5E. In particular, in ARL13B-knockout cells, the IFT-A and IFT-B complexes accumulated at ciliary tips, and GPR161 (a negative regulator of Hedgehog signaling) could not exit cilia in response to stimulation with Smoothened agonist. This abnormal phenotype was rescued by the exogenous expression of wild-type ARL13B, as well as by its mutant defective in the interaction with IFT-B, but not by its mutants defective in INPP5E binding or in ciliary localization. Thus, ARL13B regulates IFT-A-mediated retrograde protein trafficking within cilia through its interaction with INPP5E.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Nozaki
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Katoh
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Terada
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Michisaka
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Teruki
authors.initials: T
authors.lastname: Funabashi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Senye
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo 204-8588, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kontani
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan kazunaka@pharm.kyoto-u.ac.jp.
authors.forename: Kazuhisa
authors.identifier: 0000-0001-7701-7183
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D020727:ADP-Ribosylation Factors / Q000737:chemistry / Q000378:metabolism*; D000015:Abnormalities, Multiple / Q000378:metabolism*; D000595:Amino Acid Sequence; D001692:Biological Transport; D002531:Cerebellum / Q000002:abnormalities* / Q000378:metabolism; D002923:Cilia / Q000378:metabolism*; D005124:Eye Abnormalities / Q000378:metabolism*; D005407:Flagella / Q000378:metabolism; D055786:Gene Knockout Techniques; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D052177:Kidney Diseases, Cystic / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D021382:Protein Sorting Signals; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D012160:Retina / Q000002:abnormalities* / Q000378:metabolism; D000099182:Phosphoinositide 5-Phosphatases
chemical_list: D020727:ADP-Ribosylation Factors; D047908:Intracellular Signaling Peptides and Proteins; D010744:Phosphoric Monoester Hydrolases; D021382:Protein Sorting Signals; D011506:Proteins; D043562:Receptors, G-Protein-Coupled; D000099182:Phosphoinositide 5-Phosphatases; C000588604:GPR161 protein, human; C116465:TULP3 protein, human; C530391:ARL13B protein, human
keywords: ARL13B; Cilia; IFT-A complex; IFT-B complex; INPP5E; VIP assay