Interleukin-3 receptor (IL-3R (or CD123 for the alpha subunit))

The **Interleukin‑3 receptor** is a heterodimeric cell surface protein complex belonging to the type I cytokine receptor family. It consists of a unique alpha chain (CD123) paired with a common beta subunit shared by receptors for interleukin‑5 and granulocyte-macrophage colony-stimulating factor. The primary function of this receptor is to mediate the effects of interleukin‑3, which include promoting proliferation, differentiation, and survival of hematopoietic progenitor cells. The IL‑3 receptor is expressed on various blood-forming cells—including basophils, plasmacytoid dendritic cells, certain T/B lymphocytes upon activation—and is notably overexpressed in several hematologic malignancies such as acute myeloid leukemia. Therapeutically, it serves as an important target; drugs like tagraxofusp exploit its high expression on malignant blasts by delivering cytotoxic payloads directly into these cancerous cells. However, its presence on normal progenitors poses safety challenges related to bone marrow suppression or immune modulation[1][4][5][6].

Other names

IL-3RCD123 (specifically refers to the alpha subunit)Interleukin-3 receptor alpha chainIL3RA

– Ligand-directed cytotoxicity via fusion proteins or antibody-drug conjugates that bind CD123 and deliver toxins to malignant cells[1] – Blockade of signal transduction pathways essential for leukemic cell survival and proliferation[1]