Coordinate transcriptional and translational repression of p53 by TGF-?1 impairs the stress response.

ABSTRACT: Cellular stress results in profound changes in RNA and protein synthesis. How cells integrate this intrinsic, p53-centered program with extracellular signals is largely unknown. We demonstrate that TGF-?1 signaling interferes with the stress response through coordinate transcriptional and translational repression of p53 levels, which reduces p53-activated transcription, and apoptosis in precancerous cells. Mechanistically, E2F-4 binds constitutively to the TP53 gene and induces transcription. TGF-?1-activated Smads are recruited to a composite Smad/E2F-4 element by an E2F-4/p107 complex that switches to a Smad corepressor, which represses TP53 transcription. TGF-?1 also causes dissociation of ribosomal protein RPL26 and elongation factor eEF1A from p53 mRNA, thereby reducing p53 mRNA association with polyribosomes and p53 translation. TGF-?1 signaling is dominant over stress-induced transcription and translation of p53 and prevents stress-imposed downregulation of Smad proteins. Thus, crosstalk between the TGF-? and p53 pathways defines a major node of regulation in the cellular stress response, enhancing drug resistance.

SUBMITTER: Lopez-Diaz FJ 

PROVIDER: S-EPMC3735454 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature