This family consists of several eukaryotic immediate early response (IER) 2 and 5 proteins. The role of IER5 is unclear although it play an important role in mediating the cellular response to mitogenic signals [1,2]. Again, little is known about the function of IER2 although it is thought to play a role in mediating the cellular responses to a variety of extracellular signals [3,4].

1: Ier5, a novel member of the slow-kinetics immediate-early genes. Williams M, Lyu MS, Yang YL, Lin EP, Dunbrack R, Birren B, Cunningham J, Hunter K; Genomics 1999;55:327-334. PMID:10049588

2: Gene expression in the brain across the sleep-waking cycle. Cirelli C, Tononi G; Brain Res 2000;885:303-321. PMID:11102586

3: Pip92: a short-lived, growth factor-inducible protein in BALB/c 3T3 and PC12 cells. Charles CH, Simske JS, O'Brien TP, Lau LF; Mol Cell Biol 1990;10:6769-6774. PMID:2247083

4: Intracellular calcium mobilization induces immediate early gene pip92 via Src and mitogen-activated protein kinase in immortalized hippocampal cells. Chung KC, Sung JY, Ahn W, Rhim H, Oh TH, Lee MG, Ahn YS; J Biol Chem 2001;276:2132-2138. PMID:11053438