Sign in Subscribe
Universities and colleges

Nucleophosmin Blocks Mitochondrial Localization of p53 and Apoptosis

Strategic Insights

— 1 min read

Scientists at the University of Kentucky have made a groundbreaking discovery about the role of p53 in apoptosis, a process by which cells self-destruct in response to stress or damage. According to a study published in the Journal of Biological Chemistry, overexpression of nucleophosmin (NPM) significantly suppresses apoptosis by blocking the mitochondrial localization of p53. This finding suggests that NPM may play a crucial role in protecting cells from apoptosis by reducing the levels of p53 in mitochondria.

Key Takeaways:

  • The researchers demonstrated that overexpression of NPM suppresses 12-O-tetradecanoylphorbol 13-acetate (TPA)-mediated apoptosis in JB6 skin epithelial cells and primary epithelial cells.
  • NPM blocks the mitochondrial localization of p53, which is essential for p53-mediated apoptosis.
  • The study suggests that the presence of p53 in mitochondria plays an important role in stress-induced apoptosis.
  • NPM enhances the expression of p53 target genes p21 and bax, but the increase in Bax level without p53 in mitochondria did not lead to an increase in TPA-induced apoptosis.
  • Suppression of NPM by NPM small interfering RNA leads to an increase of p53 levels in mitochondria and apoptosis.
  • The researchers concluded that the data indicate that the presence of p53 in mitochondria plays an important role in stress-induced apoptosis and suggest that NPM may protect cells from apoptosis by reducing the mitochondrial level of p53.
  • The study provides new insights into the mechanisms of apoptosis and the role of NPM in protecting cells from stress-induced damage.

Statistics:

  • Within 1 hour following TPA treatment of JB6 cells, p53 accumulated in mitochondria.
  • The study observed a significant decrease in TPA-induced apoptosis in cells where NPM was overexpressed.
  • The authors reported that the use of NPM small interfering RNA led to an increase of p53 levels in mitochondria and apoptosis.
  • The study suggests that the presence of p53 in mitochondria is essential for TPA-induced apoptosis.
  • The researchers found that the suppression of NPM in tumor cells with a high constitutive level of NPM results in p53 translocation to mitochondria and enhances TPA-mediated apoptosis.

Sources:

  • Dhar, S.K. et al. (2009) "Nucleophosmin Blocks Mitochondrial Localization of p53 and Apoptosis." Journal of Biological Chemistry, vol. 284, no. 24, 2009, pp. 16409-16418.
  • S.K. Dhar, University of Kentucky, Graduate Center Toxicology, Lexington, KY 40536, USA.
  • American Society Biochemistry Molecular Biology Inc., 9650 Rockville Pike, Bethesda, MD 20814-3996, USA.

Read more