Transient Hysteresis in CDK4/6 Activity Underlies Passage of the Restriction Point in G1 (Molecular Cell)

Chung et al. show that the commitment to mitogen-independent cell-cycle progression in G1, termed the restriction point (R), is not executed by an assumed feedback loop from cyclin E-CDK2 to Rb but rather by probabilistic short-term maintenance of CDK4/6 activity.