title: A conserved flagella-associated protein in Chlamydomonas, FAP234, is essential for axonemal localization of tubulin polyglutamylase TTLL9.
abstract: Tubulin undergoes various posttranslational modifications, including polyglutamylation, which is catalyzed by enzymes belonging to the tubulin tyrosine ligase-like protein (TTLL) family. A previously isolated Chlamydomonas reinhardtii mutant, tpg1, carries a mutation in a gene encoding a homologue of mammalian TTLL9 and displays lowered motility because of decreased polyglutamylation of axonemal tubulin. Here we identify a novel tpg1-like mutant, tpg2, which carries a mutation in the gene encoding FAP234, a flagella-associated protein of unknown function. Immunoprecipitation and sucrose density gradient centrifugation experiments show that FAP234 and TTLL9 form a complex. The mutant tpg1 retains FAP234 in the cell body and flagellar matrix but lacks it in the axoneme. In contrast, tpg2 lacks both TTLL9 and FAP234 in all fractions. In fla10, a temperature-sensitive mutant deficient in intraflagellar transport (IFT), both TTLL9 and FAP234 are lost from the flagellum at nonpermissive temperatures. These and other results suggest that FAP234 functions in stabilization and IFT-dependent transport of TTLL9. Both TTLL9 and FAP234 are conserved in most ciliated organisms. We propose that they constitute a polyglutamylation complex specialized for regulation of ciliary motility.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655 Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kubo
authors.forename: Haru-aki
authors.initials: HA
authors.lastname: Yanagisawa
authors.forename: Zhongmei
authors.initials: Z
authors.lastname: Liu
authors.forename: Rie
authors.initials: R
authors.lastname: Shibuya
authors.forename: Masafumi
authors.initials: M
authors.lastname: Hirono
authors.forename: Ritsu
authors.initials: R
authors.lastname: Kamiya
mesh_terms: D000595:Amino Acid Sequence; D054468:Axoneme / Q000201:enzymology*; D016825:Chlamydomonas reinhardtii / Q000166:cytology / Q000201:enzymology*; D017124:Conserved Sequence; D003593:Cytoplasm / Q000201:enzymology; D004795:Enzyme Stability; D005407:Flagella / Q000201:enzymology; D010453:Peptide Synthases / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D017386:Sequence Homology, Amino Acid; D014404:Tubulin / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014404:Tubulin; D010453:Peptide Synthases; C112698:tubulin polyglutamylase