This domain is found in Plasmodium Duffy binding proteins. Plasmodium vivax and Plasmodium knowlesi merozoites invade human erythrocytes that express Duffy blood group surface determinants. The Duffy receptor family is localized in micronemes, an organelle found in all organizms of the phylum Apicomplexa. This family is closely associated on PfEMP1 proteins with PFEMP, pfam03011.