is a cell surface transmembrane protein that may act as an erythroid cell receptor, possibly as a mediator of cell adhesion. Polymorphisms in this gene are responsible for the Scianna/Radin blood group system. Two transcript variants encoding the same protein have been found for this gene.The deduced 475-amino acid protein contains an N-terminal extracellular IgV domain, a transmembrane domain, and a C-terminal cytoplasmic B30.2 domain. The cytoplasmic region also has multiple putative phosphorylation sites and a number of post-Golgi sorting signals. ERMAP does not contain the IgC domain found in mouse Ermap. FISH detected ERMAP in fetal and adult erythroblasts and reticulocytes. Immunofluorescent localization with antibody directed to the IgV domain detected ERMAP on the cell surface.