EGF-like module-containing mucin-like hormone receptor-like 1 also known as F4/80 is a protein encoded by the ADGRE1gene. EMR1 is a member of the adhesion GPCR family. Adhesion GPCRs are characterized by an extended extracellular region often possessing N-terminal protein modules that is linked to a TM7 region via a domain known as the GPCR-Autoproteolysis INducing (GAIN) domain.
EMR1 expression in human is restricted to eosinophils and is a specific marker for these cells. The murine homolog of EMR1, F4/80, is a well-known and widely-used marker of murine macrophage populations. The N-terminal fragment (NTF) of EMR1 contains 4-6 Epidermal Growth Factor-like (EGF-like) domains in human and 4-7 EGF-like domains in the mouse.
Utilizing F4/80 knockout mice, Lin et al. showed that F4/80 is not necessary for the development of tissue macrophages but is required for the induction of efferent CD8+ regulatory T cells needed for peripheral tolerance.
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