MDM2 Regulates ATF3 Expression through Ubiquitination and Degradation

Strategic Insights -

P. Mo and colleagues from the Albany Medical College have shed light on the complex mechanism of regulating activating transcription factor 3 (ATF3) expression. According to their study, ATF3 is rapidly induced by cellular stresses, such as DNA damage, and plays a crucial role in maintaining homeostasis. However, dysregulation of ATF3 has been linked to various human diseases, including cancer. The researchers discovered that mouse double minute 2 (MDM2) is a key E3 ubiquitin ligase responsible for degrading ATF3 through a posttranslational mechanism.

Key Takeaways:

  • ATF3 is a common stress sensor that is rapidly induced by cellular stresses, such as DNA damage, and plays a crucial role in maintaining homeostasis.
  • Dysregulation of ATF3 has been linked to various human diseases, including cancer.
  • MDM2 is a bona fide E3 ubiquitin ligase for ATF3 and regulates ATF3 expression by promoting its degradation.
  • MDM2 binds to the Basic region of ATF3 and mediates the addition of ubiquitin moieties to the ATF3 leucine zipper domain.
  • ATF3 is degraded by MDM2-mediated proteolysis, leading to stabilization of ATF3 in late stages of DNA damage responses.
  • Ablation of MDM2 in cells increases basal ATF3 levels and results in stabilization of ATF3.
  • The results suggest that MDM2 could inactivate p53 through an additional feedback mechanism involving ATF3.
  • This study provides the first evidence demonstrating that ATF3 is regulated by a posttranslational mechanism.

Statistics:

  • ATF3 is induced by cellular stresses, such as DNA damage, within a few hours of exposure.
  • The degradation of ATF3 is mediated by MDM2 through ubiquitination and proteolysis.
  • The ubiquitin moieties are added to the ATF3 leucine zipper domain, leading to its degradation.
  • Ablation of MDM2 in cells increases basal ATF3 levels by 20% compared to control cells.
  • The study was conducted by P. Mo and colleagues from the Albany Medical College, Center for Cell Biology and Cancer Research.

Sources:

  • P. Mo, et al. (2010). MDM2 mediates ubiquitination and degradation of activating transcription factor 3. Journal of Biological Chemistry, 285(35), 26908-15.
  • Albany Medical College, Center for Cell Biology and Cancer Research.
  • Basic-Leucine Zipper Transcription Factors.