Native architecture of the centriole proximal region reveals features underlying its 9-fold radial symmetry

Curr Biol. 2013 Sep 9;23(17):1620-8. doi: 10.1016/j.cub.2013.06.061. Epub 2013 Aug 8.


Background: Centrioles are cylindrical microtubule-based structures whose assembly is critical for the formation of cilia, flagella, and centrosomes. The centriole proximal region harbors a cartwheel that dictates the 9-fold symmetry of centrioles. Although the cartwheel architecture has been recently analyzed, how it connects to the peripheral microtubules is not understood. More generally, a high-resolution view of the proximal region of the centriole is lacking, thus limiting understanding of the underlying assembly mechanisms.

Results: We report the complete architecture of the Trichonympha centriole proximal region using cryotomography. The resulting 3D map reveals several features, including additional densities in the cartwheel that exhibit a 9-fold symmetrical arrangement, as well as the structure of the Pinhead and the A-C linker that connect to microtubules. Moreover, we uncover striking chiral features that might impart directionality to the entire centriole. Furthermore, we identify Trichonympha SAS-6 and demonstrate that it localizes to the cartwheel in vivo.

Conclusions: Our work provides unprecedented insight into the architecture of the centriole proximal region, which is key for a thorough understanding of the mechanisms governing centriole assembly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Centrioles*
  • Hypermastigia / cytology
  • Molecular Sequence Data

Associated data

  • GENBANK/AB819957
  • GENBANK/AB819958
  • GENBANK/AB819959
  • GENBANK/AB819960
  • GENBANK/AB819961