RT Journal Article
SR Electronic
T1 Phosphatase PP2A and microtubule pulling forces disassemble centrosomes during mitotic exit
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 182618
DO 10.1101/182618
A1 Stephen J. Enos
A1 Martin Dressler
A1 Beatriz Ferreira Gomes
A1 Anthony A. Hyman
A1 Jeffrey B. Woodruff
YR 2017
UL http://biorxiv.org/content/early/2017/09/12/182618.abstract
AB Centrosomes are major microtubule-nucleating organelles that facilitate chromosome segregation and cell division in metazoans. Centrosomes comprise centrioles that organize a micron-scale mass of protein called pericentriolar material (PCM) from which microtubules nucleate. During each cell cycle, PCM accumulates around centrioles through phosphorylation-mediated assembly of PCM scaffold proteins. During mitotic exit, PCM swiftly disassembles by an unknown mechanism. Here, we used Caenorhabditis elegans embryos to determine the mechanism and importance of PCM disassembly in dividing cells. We found that the phosphatase PP2A and its regulatory subunit SUR-6 (PP2ASUR-6), together with cortically directed microtubule pulling forces, actively disassemble PCM. In embryos depleted of these activities, ~25% of PCM persisted from one cell cycle into the next, resulting in cytokinetic furrow ingression errors, excessive centrosome accumulation, and embryonic death. Purified pp2ASUR-6 could dephosphorylate the major PCM scaffold protein SPD-5 in vitro. Our data suggest that PCM disassembly occurs through a combination of dephosphorylation of PCM components and catastrophic rupture of the PCM scaffold.