Fig 4. WEE1 and CDC25C regulation of preMPF and activation of MPF kinase.

(A) Approximated steady-state protein levels from studies by Potapova et al. [9] using immunoblot analysis for CCNB1T, CDK1T, CDK1P (i.e. preMPF), phosphorylated H3 S10P, APC3 (i.e. APC/CT), APC3P (i.e. APC/CP) in HeLa cells following release from synchronization in the S/G2 phase. Arrows mark points of comparison between in vitro and in silico data. (P, phosphorylated protein; T, total protein) (B) Simulation of WEE1 kinase ($k_{r2}^{\prime }$) and CDC25C phosphatase ($k_{f2}^{\prime }$) activities in regulating oscillations in CDK1T, LMNAP, APC/CT, APC/CP, CDC25CT, CDC25CP, preMPF (CCNB1:CDK1P), and active MPF kinase (CCNB1:CDK1) over the indicated time periods. Boxed area is magnified. (C) Approximated steady-state protein levels for APC3P, CDK1T, and H3 S10P from studies by Potapova et al. [9] involving chemical inhibition (+) of WEE1 kinase activity using synchronized HeLa cells compared to control. (D) Inhibition of WEE1 with inhibition of CDC25 (+) activities in synchronized HeLa cells by Potapova et al. [9] and associated changes in APC3P, CDK1T, and H3 S10P resulting in a mitotic collapse. (E) Simulated inhibition of WEE1 kinase ($k_{r2}^{\prime }$) and associated changes oscillations in CDK1T, LMNAP, APC/CT, APC/CP, CDC25CT, CDC25CP, preMPF (CCNB1:CDK1P), and active MPF kinase (CCNB1:CDK1) over the indicated time period. Also, simulated inhibition of both WEE1 ($k_{r2}^{\prime }$) and CDC25C ($k_{f2}^{\prime }$) and associated changes resulting in a mitotic collapse.