Human epidermal growth factor (EGF)–like module containing mucin-like hormone receptor 1 (EMR1) is a surface receptor with unknown function that belongs to the adhesion family of the G protein-coupled receptors (GPCR). This receptor is encoded by the ADGRE1 and like all GPCRs, contains seven transmembrane domains, an intracellular C-terminus and an extracellular N-terminus. The NH2 domain has six EGF-like domains.

Adhesion GPCRs share a long N-terminal extracellular sequences comprising multiple domains, separated from the transmembrane segments by a serine/threonine-rich domain, a feature reminiscent of mucin-like, single-span, integral membrane glycoproteins with adhesive properties^1,2.

EMR1 protein is a homolog of F4/80, a murine protein that is widely being used as a marker of murine macrophage populations¹.

Human EMR1 is exclusively expressed on mature eosinophils in the blood and bone marrow and in nasal polyps. Thus, EMR1 is considered to be a potential therapeutic target for the treatment of eosinophilic disorders^1,3.