title: Structural basis of the 9-fold symmetry of centrioles.
abstract: The centriole, and the related basal body, is an ancient organelle characterized by a universal 9-fold radial symmetry and is critical for generating cilia, flagella, and centrosomes. The mechanisms directing centriole formation are incompletely understood and represent a fundamental open question in biology. Here, we demonstrate that the centriolar protein SAS-6 forms rod-shaped homodimers that interact through their N-terminal domains to form oligomers. We establish that such oligomerization is essential for centriole formation in C. elegans and human cells. We further generate a structural model of the related protein Bld12p from C. reinhardtii, in which nine homodimers assemble into a ring from which nine coiled-coil rods radiate outward. Moreover, we demonstrate that recombinant Bld12p self-assembles into structures akin to the central hub of the cartwheel, which serves as a scaffold for centriole formation. Overall, our findings establish a structural basis for the universal 9-fold symmetry of centrioles.
authors.affiliation: Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology, EPFL, Lausanne, Switzerland.
authors.forename: Daiju
authors.initials: D
authors.lastname: Kitagawa
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vakonakis
authors.forename: Natacha
authors.initials: N
authors.lastname: Olieric
authors.forename: Manuel
authors.initials: M
authors.lastname: Hilbert
authors.forename: Debora
authors.initials: D
authors.lastname: Keller
authors.forename: Vincent
authors.initials: V
authors.lastname: Olieric
authors.forename: Miriam
authors.initials: M
authors.lastname: Bortfeld
authors.forename: Michèle C
authors.initials: MC
authors.lastname: Erat
authors.forename: Isabelle
authors.initials: I
authors.lastname: Flückiger
authors.forename: Pierre
authors.initials: P
authors.lastname: Gönczy
authors.forename: Michel O
authors.initials: MO
authors.lastname: Steinmetz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002107:Caenorhabditis / Q000737:chemistry / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D002502:Centrioles / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D011994:Recombinant Proteins; C497201:SAS-6 protein, C elegans