Send to

Choose Destination
See comment in PubMed Commons below
Mol Cell. 2004 Jan 30;13(2):241-50.

Ras induces mediator complex exchange on C/EBP beta.

Author information

Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Str. 10, 13092 Berlin, Germany.


C/EBPbeta is an intrinsically repressed transcription factor that regulates genes involved in differentiation, proliferation, tumorigenesis, and apoptosis. C/EBPbeta acts as a repressor that is turned into an activator by the Ras oncoprotein through phosphorylation of a MAPK site. C/EBPbeta activation is accompanied by a conformational change. Active and repressive C/EBPbeta interacts with multisubunit Mediator complexes through the CRSP130/Sur2 subunit. The CRSP130/Sur2 subunit is common to two distinct types of Mediator complexes, characterized by CRSP70 and CDK8 proteins as transcriptionally active and inactive Mediator, respectively. Knockdown of CRSP130/Sur2 prevents Mediator binding and transactivation through C/EBPbeta. Oncogenic Ras signaling or activating mutations in C/EBPbeta selects the transcriptionally active Mediator complex that also associates with RNA polymerase II. These results show that a Ras-induced structural alteration of C/EBPbeta determines differential gene activation through selective interaction with distinct Mediator complexes.

[Indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center