Iron-responsive elements (IREs) are specific RNA sequences found in the untranslated regions of certain mRNAs. They play a crucial role in regulating the expression of genes involved in iron metabolism, helping cells respond to varying levels of iron availability. When iron levels are low, proteins called iron regulatory proteins (IRPs) bind to IREs, stabilizing the mRNA and promoting the production of proteins that help acquire and utilize iron. Conversely, when iron levels are sufficient, IRPs do not bind to IREs, leading to the degradation of the mRNA and reduced production of these proteins.