DNA mismatch repair-dependent activation of c-Abl/p73α/GADD45α- mediated apoptosis

Shan Li Long, Julio C. Morales, Arlene Hwang, Mark W. Wagner, David A. Boothman

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Cells with functional DNA mismatch repair (MMR) stimulate G2 cell cycle checkpoint arrest and apoptosis in response to N-methyl-N′- nitro-N-nitrosoguanidine (MNNG). MMR-deficient cells fail to detect MNNG-induced DNA damage, resulting in the survival of "mutator" cells. The retrograde (nucleus-tocytoplasm) signaling that initiates MMR-dependent G 2 arrest and cell death remains undefined. Since MMR-dependent phosphorylation and stabilization of p53 were noted, we investigated its role(s) in G2 arrest and apoptosis. Loss of p53 function by E6 expression, dominant-negative p53, or stable p53 knockdown failed to prevent MMR-dependent G2 arrest, apoptosis, or lethality. MMR-dependent c-Abl-mediated p73α and GADD45α protein up-regulation after MNNG exposure prompted us to examine c-Abl/p73α/GADD45α signaling in cell death responses. STI571 (Gleevec™, a c-Abl tyrosine kinase inhibitor) and stable c-Abl, p73α, and GADD45α knockdown prevented MMR-dependent apoptosis. Interestingly, stable p73α knockdown blocked MMR-dependent apoptosis, but not G2 arrest, thereby uncoupling G2 arrest from lethality. Thus, MMR-dependent intrinsic apoptosis is p53-independent, but stimulated by hMLH1/c-Abl/p73α/GADD45α retrograde signaling.

Original languageEnglish (US)
Pages (from-to)21394-21403
Number of pages10
JournalJournal of Biological Chemistry
Issue number31
StatePublished - Aug 1 2008

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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