Core Concepts
Centrosome age disrupts spindle symmetry via microtubule nucleation.
Abstract
The study explores how centrosome age influences spindle symmetry in human epithelial and fibroblastic cells. Centrosomes of different ages lead to subtle spindle asymmetries, affecting daughter cell sizes. Pericentrin, Cdk5Rap2, and γ-tubulin accumulate preferentially on old centrosomes, impacting microtubule nucleation. The presence of daughter centrioles dampens the asymmetry induced by grandmother centrioles. Depletion of pericentrin or TPX2 restores spindle symmetry, highlighting their role in breaking spindle symmetry based on centrosome age. Additionally, Plk1 binding to cenexin drives spindle size and polar chromosome asymmetries.
Stats
For 2:2 cells SAI = 1.4% ± 6.2%, n=133 cells, p = 0.0104; for 1:1 cells = 4.1 ± 7.3%, n=96 cells, p <0.0001; for 1:0 cells = 19.3% ± 11.2%, n=111 cells, p <0.0001; and for 0:0 cells = 0.9% ± 13.3%, n=77 cells, p = 0.54 in one-sample t-tests.
Means of (G) pericentrin and (H) TPX2 fluorescence intensity at spindle poles in siCtrl (n=44 cells), siPCNT (n=45 cells) and siTPX2-treated (n=30 cells) RPE1 GFP-centrin1 cells showed significant differences (p < 0.0001).
Relative TPX2 distribution means of 3% ± 6.5%, n=36 cells, p = 0.0210 in WT RPE1 GFP-centrin1 vs., mScarlet-cenexin S796A with a mean of -0% ±5%, n=55cells, p = .5917.
Quotes
"Old centrosomes have a higher microtubule nucleation capacity."
"Pericentrin contributes to TPX2 recruitment at spindle poles."
"The cenexin-bound pool of Plk1 breaks spindle symmetry."