ERK2 stimulates transcription by anchoring CDK9 to the promoter in a kinase activity-independent manner.

The transcription factor MYC regulates cell proliferation, transformation, and survival in response to growth factor signaling that is mediated in part by the kinase activity of ERK2. Because ERK2 can also bind to DNA to modify gene expression, we investigated whether it more directly regulates transcription. We identified ERK2 binding sites in the promoter and detected ERK2 at the promoter in various serum-stimulated cell types. Expression of nuclear-localized ERK2 constructs in serum-starved cells revealed that ERK2 in the nucleus-regardless of its kinase activity-increased mRNA expression and MYC protein abundance. ERK2 bound to the promoter through its amino-terminal insert domain and to the cyclin-dependent kinase CDK9 (which activates RNA polymerase II) through its carboxyl-terminal conserved docking domain. Both interactions were essential for ERK2-induced expression, and depleting ERK impaired CDK9 occupancy and RNA polymerase II progression at the promoter. Artificially tethering CDK9 to the promoter by fusing it to the ERK2 insert domain was sufficient to stimulate expression in serum-starved cells. Our findings demonstrate a role for ERK2 at the promoter acting as a kinase-independent anchor for the recruitment of CDK9 to promote expression.