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 t he c-fos SRE is the target of several extracellular signal regulated p athways. Phosphorylation of the TCF Elk-1 is a key event in the activa tion of this complex. We demonstrate that ERK2/p42 phosphorylation of Elk-1 stimulates its recruitment into ternary complexes with SRF. More over, phosphorylation of Elk-1 also stimulates its autonomous SRF-inde pendent binding to high affinity binding sites. Thus part of the effec t of ERK2/p42 phosphorylation is to stimulate DNA-binding by the ETS D IVA-binding domain of Elk-1.