Description
Interleukin 2 receptor, alpha, also called IL2R, IL2R, Alpha Chain or CD25, is a protein that in humans is encoded by the IL2RA gene. IL2RA is composed of strand-swapped sushi-like domains, unlike the classical cytokine receptor fold. As a result of this domain swap, it uses a composite surface to dock into a groove on IL2 that also serves as a binding site for antagonist drugs. Homodimeric alpha chains result in low-affinity receptor, while homodimeric beta chains produce a medium-affinity receptor. Normally an integral-membrane protein, soluble IL2RA has been isolated and determined to result from extracellular proteolyisis. Infection by the protozoan Trypanosoma cruzi causes Chagas disease, characterized by a reduction in the amount of IL2RA expressed on the surface of immune cells. This leads to chronic immune suppression, becoming increasingly severe over the course of many years and ultimately resulting in death if left untreated