Myc synthesis driven by growth signals (S)

Rb dephosphorylation

Myc decay

E2F decay

CycE decay

CycD decay

Rb decay

Phosphorylated Rb decay

Rb-E2F complex decay

CycD synthesis driven by growth signals

E2F synthesis by a synergy between Myc and E2F autocatalysis. Since neither Myc nor E2F forms a homodimer, we assumed no cooperativity in gene activation mediated by these factors, and used the Hill coefficient of 1.0. Using Hill coefficient greater than 1.0 will not change the qualitative behavior of system dynamics

CycE synthesis driven by E2F

CycD synthesis driven by Myc

Constitutive Rb synthesis

E2F dissociation from Rb-E2F complex by CycD- and CycE-mediated phosphorylation

E2F titration by Rb via E2F-Rb complex formation

Rb phosphorylation by CycD and CycE