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Figure 1 | Cell Division

Figure 1

From: Differential requirement of cyclin-dependent kinase 2 for oligodendrocyte progenitor cell proliferation and differentiation

Figure 1

Control of cell cycle progression. Mitogenic signalling results in cyclin D synthesis, formation of active Cdk4/6-cyclin D complexes and initial phosphorylation of Rb. Partially phosphorylated Rb still binds to transcription factor E2F but some genes can be transcribed, such as cyclin E which binds to and activates Cdk2. It is generally accepted that Cdk2-dependent phosphorylation of Rb results in its complete inactivation, which allows induction of the E2F-responsive genes that are needed to drive cells through the G1/S transition. R represents the restriction point that separates the mitogen-dependent early G1 phase from the mitogen-independent late G1 phase. Cdk2 associated to cyclin A controls progression through S phase. Cdk1-cyclin A complex is responsible for G2 phase progression. Cdk1 associated to cyclin B is essential for both G2/M transition and mitosis progression.

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