Fig. 6. p53-MCL as a centrosome-associated sensor.

a Upper panel: schematic representation of the mitotic surveillance pathway¹⁶ activated by centrosome-loss induced by centrinone treatment¹⁵. Lower panel: schematic representation of the accumulation of the p53Ser15^P foci induced by inhibition of MT dynamics by nocodazole-treatment²³. b Cell passaging assays were performed with the indicated cells after the addition of DMSO (ctr) or centrinone (cent) and after their washout. HeLa and RPE1 cells behaved as reported¹⁵. The nontransformed AHH1 LCL irreversibly arrested after centrinone treatment as well as RPE1 cells. c Time course analysis of centrinone-induced centrosome-loss in AHH1 mitotic cells. The percentage of mitoses with 0, 1, and 2 centrosomes has been calculated by analyzing at least 50 mitoses per time point. d Representative IF images of ctr and cent-treated AHH1 cells (48 h time point) obtained by double IF for γ-tubulin/p53 and γ-tubulin/phosho-p53Ser15 show that centrosome-loss associated with the formation of extra-centrosomal p53 foci that can be phosphorylated at Ser15. Histograms show the percentages of mitotic cells with p53 and p53Ser15^P foci at the indicated time-points after centrinone addition. e The indicated cells, ctr or cent treated for 8 days, were analyzed for DNA content by flow cytometry. The relative cell-cycle profiles show that AHH1 cells accumulate in the G1 phase of the cell cycle. RPE1 and HeLa cells were used as controls and behaved similarly to previous report¹⁵