a transcription factor of the Ets family and the ternary complex factor (TCF) subfamily. Forms a ternary complex by binding to the serum response factor and the serum response element in the promoter of the c-fos proto-oncogene. Mediates gene activity in response to serum and growth factors. Phosphorylated by MAP kinase pathways at a cluster of S/T motifs at its C-terminus; phosphorylation at these sites is critical for transcriptional activation by Elk-1. Two alternatively-spliced isoforms have been described. Note: This description may include information from UniProtKB.