Electron cryo-tomography provides insight into procentriole architecture and assembly mechanism

Elife. 2019 Feb 11;8:e43434. doi: 10.7554/eLife.43434.

Abstract

Centriole is an essential structure with multiple functions in cellular processes. Centriole biogenesis and homeostasis is tightly regulated. Using electron cryo-tomography (cryoET) we present the structure of procentrioles from Chlamydomonas reinhardtii. We identified a set of non-tubulin components attached to the triplet microtubule (MT), many are at the junctions of tubules likely to reinforce the triplet. We describe structure of the A-C linker that bridges neighboring triplets. The structure infers that POC1 is likely an integral component of A-C linker. Its conserved WD40 β-propeller domain provides attachment sites for other A-C linker components. The twist of A-C linker results in an iris diaphragm-like motion of the triplets in the longitudinal direction of procentriole. Finally, we identified two assembly intermediates at the growing ends of procentriole allowing us to propose a model for the procentriole assembly. Our results provide a comprehensive structural framework for understanding the molecular mechanisms underpinning procentriole biogenesis and assembly.

Keywords: cell biology; centriole; chlamydomonas reinhardtii; electron cryo-tomography; microtubule triplet; procentriole; structure heterogeneity; subtomogram averaging.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle / genetics
  • Cell Cycle Proteins / chemistry
  • Cell Cycle Proteins / genetics
  • Centrioles / genetics
  • Centrioles / ultrastructure*
  • Chlamydomonas reinhardtii / ultrastructure*
  • Cryoelectron Microscopy*
  • Electron Microscope Tomography*
  • Microtubules / ultrastructure

Substances

  • Cell Cycle Proteins