IER2 is a 223 amino acid protein belonging to the immediate early response (IER) family. IER proteins are the first gene products to be induced during growth stimulation and/or arrest. IER2 expression can be induced by growth factors,12-O-tetradecanoylphorbol-13-acetate (TPA) or Okadaic acid. The coding region of IER2 contains regions of similarity to the transcription factor proteins that are encoded by the Jun oncogene family, possibly indicating a role for IER2 in transcription regulation. Further evidence for this role includes a GUUUG sequence in the 3’ flanking region of IER2, which is believed to be a mRNA degradation signal similar to those found in transcription regulators.