Cyclin A-dependent Phosphorylation of the ETS-related Protein, MEF, Restricts Its Activity to the G1 Phase of the Cell Cycle

Yasushi Miyazaki, Piernicola Boccuni, Shifeng Mao, Jin Zhang, Hediye Erdjument-Bromage, Paul Tempst, Hiroaki Kiyokawa, Stephen D. Nimer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


MEF, a recently identified member of the E74 family of ETS-related transcription factors, is a strong transcriptional activator of cytokine gene expression. Using a green fluorescent protein gene reporter plasmid regulated by an MEF-responsive promoter, we determined that the transcriptional activity of MEF is largely restricted to the G1 phase of the cell cycle. MEF-dependent transcription was suppressed by the expression of cyclin A but not by cyclin D or cyclin E. This effect was due to the kinase activity generated by cyclin A expression, as co-expression of the cyclin-dependent kinase inhibitors p21 or p27, or a dominant negative form of CDK2 (DNK2), abrogated the reduction of MEF transcriptional activity by cyclin A. Cyclin A-CDK2 phosphorylated MEF protein in vitro more efficiently than cyclin D-CDK4 or cyclin E-CDK2, and phosphorylation of MEF by cyclin A-CDK2 reduced its ability to bind DNA. We determined one site of phosphorylation by cyclin A-CDK2 at the C terminus of MEF, using mass-spectrometry; mutation of three serine or threonine residues in this region significantly reduced phosphorylation of MEF by cyclin A and reduced cyclin A-mediated suppression of its transactivating activity. These amino acid substitutions also reduced the restriction of MEF activity to G1. Phosphorylation of MEF by the cyclin A-CDK2 complex controls its transcriptional activity during the cell cycle, establishing a novel link between the ETS family of proteins and the cell cycle machinery.

Original languageEnglish (US)
Pages (from-to)40528-40536
Number of pages9
JournalJournal of Biological Chemistry
Issue number44
StatePublished - Nov 2 2001

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Cell Biology


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