IRP1 Rabbit Polyclonal Antibody

Iron Regulatory Protein 1 (IRP1) is a core dual-function protein in animal cells that maintains iron homeostasis, operating via a reversible "iron-sulfur switch" that allows it to toggle between two mutually exclusive roles. When intracellular iron is sufficient, IRP1 assembles a [4Fe-4S] iron-sulfur cluster and functions as enzymatically active cytosolic aconitase, catalyzing the isomerization of citrate to isocitrate. Conversely, when iron is scarce or under oxidative stress, this cluster disassembles, and IRP1 rapidly changes conformation into an RNA-binding protein. In this form, it binds with high affinity to iron-responsive elements (IREs) in the untranslated regions of specific mRNAs, thereby regulating the expression of key proteins such as ferritin (by suppressing translation) and transferrin receptor (by stabilizing the mRNA) to restore iron balance. Furthermore, this functional switch is regulated by modifications including phosphorylation. When the iron-sulfur cluster assembly pathway is compromised, the apo form of IRP1 is targeted for degradation by the ubiquitin-proteasome system, providing an additional layer of control over its activity.