Centrioles resist forces applied on centrosomes during G2/M transition.
BACKGROUND
Centrosome movements at the onset of mitosis result from a balance between the pulling and pushing forces mediated by microtubules. The structural stability of the centrosome core structure, the centriole pair, is correlated with a heavy polyglutamylation of centriole tubulin.


RESULTS
Using HeLa cells stably expressing centrin-green fluorescent protein as a centriole marker, we monitored the effect of microinjecting an anti-(polyglutamylated tubulin) monoclonal antibody, GT335, in G1/S or G2 cells. In contrast with the slow effect of the monoclonal antibody GT335 during interphase, a dramatic and rapid centrosome fragmentation occurred in cells microinjected in G2 that was both Eg5- and dynein-dependent. Inhibition of either one of these two motors significantly decreased the scattering of centrosome fragments, and inhibition of centrosome segregation by impairing microtubule dynamics abolished centrosome fragmentation.


CONCLUSIONS
Our results demonstrate that the compact structure of the mitotic centrosome is capable of absorbing most of the pulling and pushing forces during G2/M transition and suggest that centrosomes could act as mechanosensors integrating tensions during cell division.
Abal
Miguel
M
Institut Curie, UMR 144-CNRS, 26 rue d'Ulm, 75248 Paris cedex 05, France.
Keryer
Guy
G
Bornens
Michel
M
D000911:Antibodies, Monoclonal / Q000737:chemistry; D002453:Cell Cycle; D002455:Cell Division; D002502:Centrioles / Q000378:metabolism / Q000648:ultrastructure*; D018385:Centrosome / Q000378:metabolism / Q000648:ultrastructure; D004398:Dyneins / Q000378:metabolism; D016193:G1 Phase; D016195:G2 Phase; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D008954:Models, Biological; D020409:Molecular Motor Proteins; D010455:Peptides / Q000737:chemistry; D016196:S Phase; D013997:Time Factors; D014404:Tubulin / Q000737:chemistry
D000911:Antibodies, Monoclonal; C470243:KIF11 protein, human; D020409:Molecular Motor Proteins; D010455:Peptides; D014404:Tubulin; D049452:Green Fluorescent Proteins; C097188:polyglutamine; D004398:Dyneins; D016547:Kinesins