Erythropoietin receptor and beta common receptor heterodimer (EPOR-βcR heterodimer)

The erythropoietin receptor and beta common receptor heterodimer (EPOR-βcR; also known as the "innate repair receptor" or IRR) is a non-hematopoietic receptor complex composed of the erythropoietin receptor (EPOR) and the beta common receptor subunit (βcR/CD131). Unlike the classical EPOR homodimer responsible for erythropoiesis, the EPOR-βcR heterodimer mediates tissue-protective effects of erythropoietin and related peptides in organs such as the brain, heart, and kidney in models of ischemic and inflammatory injury. Activation of this receptor complex leads to anti-apoptotic and pro-survival signaling through JAK2, PI3K/Akt, and eNOS, increasing nitric oxide production and promoting tissue regeneration. The complex is of therapeutic interest for tissue protection and repair, and erythropoietin derivatives that selectively target this heterodimer are in development for disorders such as stroke, myocardial infarction, and acute kidney injury. It is not involved in classical erythropoiesis, and specific activation can avoid the negative side effects of red blood cell overproduction. The structural and biological existence of the complex is supported by co-immunoprecipitation, pharmacology, and tissue-protection studies, though some structural details are still debated.

Other names

Innate repair receptor (IRR)Tissue-protective receptorEPOR/βcR heterodimerEPOR/CD131 complexErythropoietin non-hematopoietic receptor

Erythropoietin and derivatives bind the EPOR-βcR heterodimer, activating downstream signaling that is distinct from the classical EPOR homodimer, leading to tissue-protective and anti-inflammatory effects but not erythropoiesis. Activation of signaling pathways including JAK2/STAT5, PI3K/Akt, Src kinase, and eNOS (endothelial nitric oxide synthase), leading to increased nitric oxide production and cell survival. Carbamylated EPO selectively activates this heterodimer, which mediates tissue protection without stimulating red blood cell production.