Reactome: A Curated Pathway Database

p53-Independent DNA Damage Response (R-HSA-69610)

Species Homo sapiens


In response to DNA damage due to exposure to ultraviolet light or to ionizing radiation, Cdc25A is phosphorylated by Chk1 or Chk2. The phosphorylation of Cdc25A at ser-123, in response to DNA damage from ionizing radiation is a signal for ubiquitination and subsequent degradation of Cdc25A. The destruction of Cdc25A prevents the normal G1/S transition. Cdc25A is required for the activation of the Cyclin E:Cdk2 complexes via dephosphorylation.

Chk1 is activated in response to DNA damage due to uv light. However, the phosphorylation occurs at a different site.

Locations in the PathwayBrowser
Literature References
pubMedId Title Journal Year
11298456 The ATM-Chk2-Cdc25A checkpoint pathway guards against radioresistant DNA synthesis. Nature 2001