Elk-1 is a member of the Ets family of transcription factors and of the ternary complex factor (TCF) subfamily. Elk-1 is a nuclear target for the ras-raf-MAPK signaling cascade. Elk-1 produces multiple isoforms by using alternative translational start codons and by alternative splicing. Related pseudogenes have been identified on chromosomes 7 and 14. Proteins of the TCF subfamily form a ternary complex by binding to the the serum response factor and the serum response element in the promoter of the c-fos proto-oncogene. Located predominantly in the nucleus, Elk-1′s nuclear localization is essential for binding to DNA and modulating the transcription of immediate early genes such as c-Fos, which are pivotal in cellular responses to growth signals and MAPK/ERK signaling pathways.