ERK2/p42 MAP kinase stimulates both autonomous and SRF-dependent DNA binding by Elk-1

A ternary complex comprised of SRF, ternary complex factor (TCF) and the c-fos SRE is the target of several extracellular signal regulated pathways. Phosphorylation of the TCF Elk-1 is a key event in the activation of this complex. We demonstrate that ERK2/p42 phosphorylation of Elk-1 stimulates its recruitment into ternary complexes with SRF. Moreover, phosphorylation of Elk-1 also stimulates its autonomous SRF-independent binding to high affinity binding sites. Thus part of the effect of ERK2/p42 phosphorylation is to stimulate DNA-binding by the ETS DNA-binding domain of Elk-1.