title: Intraflagellar transport delivers tubulin isotypes to sensory cilium middle and distal segments.
abstract: Sensory cilia are assembled and maintained by kinesin-2-dependent intraflagellar transport (IFT). We investigated whether two Caenorhabditis elegans α- and β-tubulin isotypes, identified through mutants that lack their cilium distal segments, are delivered to their assembly sites by IFT. Mutations in conserved residues in both tubulins destabilize distal singlet microtubules. One isotype, TBB-4, assembles into microtubules at the tips of the axoneme core and distal segments, where the microtubule tip tracker EB1 is found, and localizes all along the cilium, whereas the other, TBA-5, concentrates in distal singlets. IFT assays, fluorescence recovery after photobleaching analysis and modelling indicate that the continual transport of sub-stoichiometric numbers of these tubulin subunits by the IFT machinery can maintain sensory cilia at their steady-state length.
authors.affiliation: Department of Molecular and Cellular Biology, University of California at Davis, One Shields Avenue, 145-B Briggs Hall, Davis, California 95616, USA.
authors.forename: Limin
authors.initials: L
authors.lastname: Hao
authors.forename: Melanie
authors.initials: M
authors.lastname: Thein
authors.forename: Ingrid
authors.initials: I
authors.lastname: Brust-Mascher
authors.forename: Gul
authors.initials: G
authors.lastname: Civelekoglu-Scholey
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
authors.forename: Seyda
authors.initials: S
authors.lastname: Acar
authors.forename: Bram
authors.initials: B
authors.lastname: Prevo
authors.forename: Shai
authors.initials: S
authors.lastname: Shaham
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Scholey
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism; D005407:Flagella / Q000378:metabolism*; D036681:Fluorescence Recovery After Photobleaching; D040542:Mechanotransduction, Cellular; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D021381:Protein Transport; D012677:Sensation; D013997:Time Factors; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; C405804:EB1 microtubule binding proteins; D008869:Microtubule-Associated Proteins; D014404:Tubulin