1. Stable centrosomal roots disentangle to allow interphase centriole independence
- Author
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Robert Mahen, Mahen, Robert [0000-0002-4748-3690], and Apollo - University of Cambridge Repository
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Life Sciences & Biomedicine - Other Topics ,0301 basic medicine ,Centrosomes ,Centriole ,PROTEIN ,Centrosome cycle ,Cell Cycle Proteins ,Biochemistry ,Microtubules ,Cell Fusion ,0302 clinical medicine ,Small interfering RNAs ,Cell Cycle and Cell Division ,COHESION ,Biology (General) ,Cytoskeleton ,Centrioles ,Anaphase ,Pericentriolar material ,Staining ,0303 health sciences ,Microscopy ,Chromosome Biology ,General Neuroscience ,Cell Staining ,Light Microscopy ,CILIARY ROOTLET ,11 Medical And Health Sciences ,C-NAP1 ,Cell biology ,Nucleic acids ,Cell Processes ,Rootletin ,Interphase ,Cellular Structures and Organelles ,General Agricultural and Biological Sciences ,Life Sciences & Biomedicine ,Research Article ,Signal Transduction ,Biochemistry & Molecular Biology ,Fluorescence Recovery after Photobleaching ,QH301-705.5 ,Mitosis ,ORGANIZATION ,Biology ,Protein Serine-Threonine Kinases ,Research and Analysis Methods ,Green Fluorescent Protein ,Time-Lapse Imaging ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Cell Line, Tumor ,Proto-Oncogene Proteins ,Genetics ,KINASE ,Ciliary rootlet ,Humans ,CYCLE ,Non-coding RNA ,030304 developmental biology ,CILIOGENESIS ,Centrosome ,Science & Technology ,General Immunology and Microbiology ,Biology and Life Sciences ,Proteins ,Epithelial Cells ,Cell Biology ,06 Biological Sciences ,MOTHER CENTRIOLE ,Gene regulation ,Luminescent Proteins ,Cytoskeletal Proteins ,030104 developmental biology ,Gene Expression Regulation ,Specimen Preparation and Treatment ,CELLS ,RNA ,Gene expression ,07 Agricultural And Veterinary Sciences ,030217 neurology & neurosurgery ,Developmental Biology ,HeLa Cells - 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., Author summary Many subcellular organelles are not enclosed by a lipid membrane but instead exist freely in the cellular interior. How the number and position of such non–membrane-bound organelles are maintained is a general unanswered question. Here, I study this problem by focusing on the centrosome—an organelle that nucleates microtubules in fundamental cellular processes. Despite much work characterising the properties of centrosomes, little is known about centrosomal fibres, called roots, which have been suggested to maintain a single centrosome. Using a combination of genome editing, cell fusion, and live-cell imaging, I show that roots are diffusionally stable polymers that assemble slowly over many hours and are able to disentangle as centrosomes transiently split apart into 2 separate units held by the fibres. I propose a model of centrosome number and position regulation using stable fibres, which project outwards into the cytoplasm to form an interface with the surrounding cellular milieu. This model could help our understanding of how organelle position and number are maintained in cells. more...
- Published
- 2018
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