Suppression of Polo like kinase 1 (PLK1) by p21Waf1 mediates the p53-dependent prevention of caspase-independent mitotic death

► Suppression of Plk1 expression is dependent on p21Waf1. ► The p21Waf1-dependent suppression of Plk1 maintains damage-induced p53 activation. ► Expression of Plk1 disrupts the interaction of p53 with target gene promoters. ► Suppression of Plk1 is needed for p53-mediated inhibition of mitotic death.