Inhibition of TFII-I-dependent cell cycle regulation by p53

Zana P. Desgranges, Jinwoo Ahn, Maria B. Lazebnik, Todd Ashworth, Caleb Lee, Richard C. Pestell, Naomi Rosenberg, Carol Prives, Ananda L. Roy

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)

Abstract

The multifunctional transcription factor TFII-I is tyrosine phosphorylated in response to extracellular growth signals and transcriptionally activates growth-promoting genes. However, whether activation of TFII-I also directly affects the cell cycle profile is unknown. Here we show that under normal growth conditions, TFII-I is recruited to the cyclin D1 promoter and transcriptionally activates this gene. Most strikingly, upon cell cycle arrest resulting from genotoxic stress and p53 activation, TFII-I is ubiquitinated and targeted for proteasomal degradation in a p53- and ATM (ataxia telangiectasia mutated)-dependent manner. Consistent with a direct role of TFII-I in cell cycle regulation and cellular proliferation, stable and ectopic expression of wild-type TFII-I increases cyclin D1 levels, resulting in accelerated entry to and exit from S phase, and overcomes p53-mediated cell cycle arrest, despite radiation. We further show that the transcriptional regulation of cyclin D1 and cell cycle control by TFII-I are dependent on its tyrosine phosphorylation at positions 248 and 611, sites required for its growth signal-mediated transcriptional activity. Taken together, our data define TFII-I as a growth signal-dependent transcriptional activator that is critical for cell cycle control and proliferation and further reveal that genotoxic stress-induced degradation of TFII-I results in cell cycle arrest.

Original languageEnglish
Pages (from-to)10940-10952
Number of pages13
JournalMolecular and Cellular Biology
Volume25
Issue number24
DOIs
Publication statusPublished - Dec 2005
Externally publishedYes

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