Inhibition of centrosome protein assembly leads to p53-dependent exit from the cell cycle

Abstract

Previous evidence has indicated that an intact centrosome is essential for cell cycle progress and that elimination of the centrosome or depletion of individual centrosome proteins prevents the entry into S phase. To investigate the molecular mechanisms of centrosome-dependent cell cycle progress, we performed RNA silencing experiments of two centrosome-associated proteins, pericentriolar material 1 (PCM-1) and pericentrin, in primary human fibroblasts. We found that cells depleted of PCM-1 or pericentrin show lower levels of markers for S phase and cell proliferation, including cyclin A, Ki-67, proliferating cell nuclear antigen, minichromosome maintenance deficient 3, and phosphorylated retinoblastoma protein. Also, the percentage of cells undergoing DNA replication was reduced by >50%. At the same time, levels of p53 and p21 increased in these cells, and cells were predisposed to undergo senescence. Conversely, depletion of centrosome proteins in cells lacking p53 did not cause any cell cycle arrest. Inhibition of p38 mitogen-activated protein kinase rescued cell cycle activity after centrosome protein depletion, indicating that p53 is activated by the p38 stress pathway.

Promoter hijack reveals pericentrin functions in mitosis and the DNA damage response

“…some workers did not see such a reduction. 16 We observed longer and more aberrant spindles in pericentrin-deficient cells than in controls, and when pericentrin-deficient cells were challenged with the spindle poisons, nocodazole or taxol, they were slower than wild-type controls in satisfying the spindle checkpoint. We speculate that these observations may reflect a reduction in K-fiber attachment rate, due to the lower γ-tubulin levels in Pcntdeficient centrosomes.…”

“…Although pericentrin deficiency leads to cell cycle arrest in p53-competent cells, 15,16 DT40 cells have defective p53 signaling capacity and were expected to proliferate in the absence of pericentrin. 39,40 Nevertheless, we aimed to generate a DT40 cell line conditionally null for Pcnt.…”

“…15 A similar cell cycle delay was also seen after Pcnt knockdown in primary human fibroblasts. 16 In transformed human cells, Pcnt knockdown disrupted mitotic spindle formation and γ-tubulin, Cep192 and Cep215 recruitment to the centrosome, although no effect on microtubules was observed in interphase cells. 7,17,18 Recent findings have indicated that pericentrin cleavage by separase is required for the mitotic centriole disengagement that allows reduplication, although how its removal controls licensing is not yet established.…”

The centrosomal protein TACC3 controls paclitaxel sensitivity by modulating a premature senescence program

“…Such a growth-inhibiting effect was also reported recently following downregulation of other centrosome-associated proteins, including PCM-1 (pericentriolar material 1 protein) and pericentrin, that also predisposes cells to senescence without the induction of cell death (Srsen et al, 2006;Mikule et al, 2007). In addition, reduction of centromeric protein A (CENP-A) and mitotic arrest deficientlike 1 (Mad2), a key checkpoint protein localized at inner kinetochores, triggers premature senescence (Prencipe et al, 2009;Maehara et al, 2010).…”

Small organelle, big responsibility: the role of centrosomes in development and disease

“…Thus, cell cycle duration and cell fate determination may be linked in the neuroepithelium. Loss of centrosome integrity in cultured cells has been reported to induce senescence or p38 mitogen-activated protein kinase-dependent G1 arrest but whether these occur in cells with MCPH mutations remains to be seen [48][49][50]. Cells with abnormal centrosome numbers take longer to form a bipolar spindle and consequently show a mitotic delay [51][52][53][54][55].…”