title: Centriole structure.
abstract: Centrioles are among the largest protein-based structures found in most cell types, measuring approximately 250 nm in diameter and approximately 500 nm long in vertebrate cells. Here, we briefly review ultrastructural observations about centrioles and associated structures. At the core of most centrioles is a microtubule scaffold formed from a radial array of nine triplet microtubules. Beyond the microtubule triplets of the centriole, we discuss the critically important cartwheel structure and the more enigmatic luminal density, both found on the inside of the centriole. Finally, we discuss the connectors between centrioles, and the distal and subdistal appendages outside of the microtubule scaffold that reflect centriole age and impart special functions to the centriole. Most of the work we review has been done with electron microscopy or electron tomography of resin-embedded samples, but we also highlight recent work performed with cryoelectron microscopy, cryotomography and subvolume averaging. Significant opportunities remain in the description of centriolar structure, both in mapping of component proteins within the structure and in determining the effect of mutations on components that contribute to the structure and function of the centriole.
authors.affiliation: Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA mark.winey@colorado.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Winey
authors.affiliation: Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA The Boulder Laboratory for the 3D EM of Cells, Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
authors.forename: Eileen
authors.initials: E
authors.lastname: O'Toole
mesh_terms: D002453:Cell Cycle / Q000502:physiology*; D002502:Centrioles / Q000502:physiology* / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D055032:Electron Microscope Tomography; D008870:Microtubules / Q000648:ultrastructure*; D008958:Models, Molecular; D013045:Species Specificity
keywords: cartwheel; distal appendages; luminal density; pericentriolar material; subdistal appendages; triplet microtubules