Decrease Font Size Increase Font Size Email this page to a friend Printer Friendly Page
Life Science > Cell Biology > Learning Center > Pathway Slides & Charts  > Cell Cycle Checkpoint
Cell Signaling & Neuroscience

Cell Cycle Checkpoint

Top Border
Left Border  Right Border
Left Corner Back Download Forward Sigma-Aldrich Right Corner

Figure-3b

Cell Cycle Checkpoint and Double Strand Breaks (DSB)

The p53-binding protein 1 (53BP1)-dependent checkpoint pathway is triggered by IR and other genotoxic events that lead to DSBs. Phosphorylation of histone H2AX to γ-H2AX by ATM occurs at or near the site of DSBs and is required for subsequent phosphorylation of 53BP1 by ATM and localization of 53BP1 into nuclear foci. Additionally, 53BP1 function is critical for coupling ATM to many of its downstream targets, including the tumor suppressor p53 and structural maintenance of chromosomes protein 1 (SMC-1). In the case of the Chk2 kinase, the coupling mechanism to ATM appears to be independent of 53BP1.

Back to Top