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Stable centrosomal roots disentangle to allow interphase centriole independence.

Published version
Peer-reviewed

Type

Article

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Abstract

The centrosome is a non-membrane-bound cellular compartment consisting of 2 centrioles surrounded by a protein coat termed the pericentriolar material (PCM). Centrioles generally remain physically associated together (a phenomenon called centrosome cohesion), yet how this occurs in the absence of a bounding lipid membrane is unclear. One model posits that pericentriolar fibres formed from rootletin protein directly link centrioles, yet little is known about the structure, biophysical properties, or assembly kinetics of such fibres. Here, I combine live-cell imaging of endogenously tagged rootletin with cell fusion and find previously unrecognised plasticity in centrosome cohesion. Rootletin forms large, diffusionally stable bifurcating fibres, which amass slowly on mature centrioles over many hours from anaphase. Nascent centrioles (procentrioles), in contrast, do not form roots and must be licensed to do so through polo-like kinase 1 (PLK1) activity. Transient separation of roots accompanies centriolar repositioning during the interphase, suggesting that centrioles organize as independent units, each containing discrete roots. Indeed, forced induction of duplicate centriole pairs allows independent reshuffling of individual centrioles between the pairs. Therefore collectively, these findings suggest that progressively nucleated polymers mediate the dynamic association of centrioles as either 1 or 2 interphase centrosomes, with implications for the understanding of how non-membrane-bound organelles self-organise.

Description

Keywords

Anaphase, Cell Cycle Proteins, Cell Fusion, Cell Line, Tumor, Centrosome, Cytoskeletal Proteins, Epithelial Cells, Gene Expression Regulation, HeLa Cells, Humans, Interphase, Protein Serine-Threonine Kinases, Proto-Oncogene Proteins, Signal Transduction, Time-Lapse Imaging, Polo-Like Kinase 1

Journal Title

PLoS Biol

Conference Name

Journal ISSN

1544-9173
1545-7885

Volume Title

16

Publisher

Public Library of Science (PLoS)
Sponsorship
The Wellcome Trust https://wellcome.ac.uk/ (grant number 100090/12/Z). This work was funded by a Wellcome Trust Henry Wellcome Fellowship.