cell cycle control system

CDKs

________ are regulated by cyclins, which bind to and activate them.

retinoblastoma protein

The ________ (Rb) is a key cell cycle regulator that helps control the progression from G1 to the S phase.

Rb

________ is phosphorylated by cyclin- dependent kinases (CDKs) during the G1 phase, which releases E2F transcription factors that activate the expression of genes required for DNA synthesis.

E2F transcription factors

________ are released from the retinoblastoma protein (Rb) when Rb is phosphorylated by cyclin- dependent kinases.

early G1 phase

In the ________, Rb is hypophosphorylated and acts as a transcriptional repressor, inhibiting the expression of E2F- regulated genes.

Cyclins

________ bind to and activate CDKs, which then phosphorylate specific target proteins, leading to changes in their activity and function.

E2F transcription factors

________ are proteins that regulate the expression of genes required for DNA synthesis and are activated during the cell cycles G1 to S phase transition.