Details

Autor(en) / Beteiligte

• Li, Sam
• Fernandez, Jose-Jesus
• Marshall, Wallace F
• Agard, David A

Titel

Three-dimensional structure of basal body triplet revealed by electron cryo-tomography

Ist Teil von

• The EMBO journal, 2012-02, Vol.31 (3), p.552-562

Ort / Verlag

Chichester, UK: John Wiley & Sons, Ltd

Erscheinungsjahr

2012

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Basal bodies and centrioles play central roles in microtubule (MT)‐organizing centres within many eukaryotes. They share a barrel‐shaped cylindrical structure composed of nine MT triplet blades. Here, we report the structure of the basal body triplet at 33 Å resolution obtained by electron cryo‐tomography and 3D subtomogram averaging. By fitting the atomic structure of tubulin into the EM density, we built a pseudo‐atomic model of the tubulin protofilaments at the core of the triplet. The 3D density map reveals additional densities that represent non‐tubulin proteins attached to the triplet, including a large inner circular structure in the basal body lumen, which functions as a scaffold to stabilize the entire basal body barrel. We found clear longitudinal structural variations along the basal body, suggesting a sequential and coordinated assembly mechanism. We propose a model in which δ‐tubulin and other components participate in the assembly of the basal body. The basal body, derived from the centriole, is a microtubule‐organizing organelle that nucleates the cilium in non‐dividing cells. Cryo‐electron tomography reveals the overall structure of this organelle, and provides insights its biogenesis and function.