Loss of centrosome integrity induces p38—p53—p21-dependent G1—S arrest

Abstract

Centrosomes organize the microtubule cytoskeleton for both interphase and mitotic functions. They are implicated in cell-cycle progression but the mechanism is unknown. Here, we show that depletion of 14 out of 15 centrosome proteins arrests human diploid cells in G1 with reduced Cdk2-cyclin A activity and that expression of a centrosome-disrupting dominant-negative construct gives similar results. Cell-cycle arrest is always accompanied by defects in centrosome structure and function (for example, duplication and primary cilia assembly). The arrest occurs from within G1, excluding contributions from mitosis and cytokinesis. The arrest requires p38, p53 and p21, and is preceded by p38-dependent activation and centrosomal recruitment of p53. p53-deficient cells fail to arrest, leading to centrosome and spindle dysfunction and aneuploidy. We propose that loss of centrosome integrity activates a checkpoint that inhibits G1-S progression. This model satisfies the definition of a checkpoint in having three elements: a perturbation that is sensed, a transducer (p53) and a receiver (p21).

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).…”

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

“…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.…”

“…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.…”

CDC25B Involvement in the Centrosome Duplication Cycle and in Microtubule Nucleation

“…g-Tubulin is necessary for both the centrosome's ability to nucleate microtubules (36,40) and the integrity and replication proficiency of the centrioles (28,37,41,42); we propose that CDC25B, in indirectly controlling the level of gTuRCs at the centrosomes, regulates the centrosome duplication cycle and microtubule nucleation, and that tight regulation of its activity [for example, by CHK1 (25) and other currently unidentified kinases] is required to maintain synchrony between the centrosome and DNA replication cycles. Consistent with this idea are the observations that inhibition of CDC25B results in the failure of the centrosome to assemble both daughter centrioles 3 and microtubules, whereas overexpression of CDC25B, on the other hand, results in overduplication of centrosomes and increased microtubule nucleation.…”