High Quality Content by WIKIPEDIA articles! In Molecular biology, the Iron response element or Iron-responsive element (IRE) is a short conserved stem-loop which is bound by iron response proteins (IRPs, also named IRE-BP or IRBP). The IRE is found in UTRs (untranslated regions) of various mRNAs whose products are involved in iron metabolism. For example, the mRNA of ferritin (an iron storage protein) contains one IRE in its 5` UTR. When iron concentration is low, IRPs bind the IRE in the ferritin mRNA leading to reduced translation rates. In contrast, binding to multiple IREs in the 3` UTR of the transferrin receptor (involved in iron acquisition) leads to increased mRNA stability.