sentences:  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.