X A Simplified model of (MAP kinas one way that mitogens stimulate cell division CYTOSOL NUCLEUS SCF subunit ouno ncrcgsod increased increased p27 degradation E2F synthesis G Cak activ G./s-cdk act cyclin D-C cyclin E-Cok increased phosphorylation E2F activity ENTHY IN S PHASEA simplified model of one way that mitogens stimulate cell division