During interphase, CDC25C, phosphorylated on serine residue 216, is associated with 14-3-3 proteins, preventing nuclear import. At the onset of mitosis, dephosphorylation of S216 of Cdc25C and dissociation of 14-3-3, with phosphorylation of CDC25C on S198 by activated PLK1 promotes nuclear import (Takizawa and Morgan 2000, Toyoshima-Morimoto et al. 2002, Bonnet et al. 2008). Activating CDC25C phosphorylation and nuclear translocation may further be enhanced by activated CCNB:CDK1 complexes (Bonnet et al. 2008).