Architecture of the centriole cartwheel-containing region revealed by cryo-electron tomography

Nikolai Klena , Maeva Le Guennec , Anne-Marie Tassin (1, 2) , Hugo van Den Hoek , Philipp S. Erdmann , Miroslava Schaffer , Stefan Geimer , Gabriel Aeschlimann , Lubomir Kovacik , Yashar Sadian , Kenneth N. Goldie , Henning Stahlberg , Benjamin D. Engel , Virginie Hamel , Paul Guichard

1 I2BC - Institut de Biologie Intégrative de la Cellule
2 BIOCIL - Biogenèse et Fonction de la Structure Centriolaire et Ciliaire

Centrioles are evolutionarily conserved barrels of microtubule triplets that form the core of the centrosome and the base of the cilium. While the crucial role of the proximal region in centriole biogenesis has been well documented, its native architecture and evolutionary conservation remain relatively unexplored. Here, using cryo-electron tomography of centrioles from four evolutionarily distant species, we report on the architectural diversity of the centriole's proximal cartwheel-bearing region. Our work reveals that the cartwheel central hub is constructed from a stack of paired rings with cartwheel inner densities inside. In bothParameciumandChlamydomonas, the repeating structural unit of the cartwheel has a periodicity of 25 nm and consists of three ring pairs, with 6 radial spokes emanating and merging into a single bundle that connects to the microtubule triplet via the D2-rod and the pinhead. Finally, we identified that the cartwheel is indirectly connected to the A-C linker through the triplet base structure extending from the pinhead. Together, our work provides unprecedented evolutionary insights into the architecture of the centriole proximal region, which underlies centriole biogenesis.

Mots clés: in situ; identification; cryo-focused ion beam milling; duplication; 9-fold symmetry; basal bodies; bld10/cep135; cartwheel; centriole; chlamydomonas; cryo-electron tomography; in situ; protein; proteomic analysis; sas-6; ultrastructure; in situ Subject Categories Cell Adhesion; Polarity & Cytoskeleton; Structural Biology

Domaines: Sciences du Vivant [q-bio]

Nikolai Klena, Maeva Le Guennec, Anne-Marie Tassin, Hugo van Den Hoek, Philipp S. Erdmann, et al.. Architecture of the centriole cartwheel-containing region revealed by cryo-electron tomography. EMBO Journal, 2020, 39, pp.e106246. ⟨10.15252/embj.2020106246⟩. ⟨hal-02968383⟩