Solute Carrier Family 48, Member 1 (SLC48A1)

HRG1 expressed in HEK293 cells bound heme, and binding was stronger at pH 6 than pH 8. Mouse erythrocytes and Xenopus oocytes expressing human HRG1 acquired the ability to transport heme. The deduced 146-amino acid protein contains 4 putative transmembrane domains, residues predicted to bind heme, and a conserved tyrosine and acidic-dileucine-type sorting signal in the cytoplasmic C terminus. Northern blot analysis detected HRG1 transcripts of 1.7 and 3.1 kb highly expressed in brain, kidney, heart, and skeletal muscle, and in several human cell lines. The shorter transcript predominated. C. elegans and human HRG1 localized in a cytoplasmic punctate distribution in transfected HEK293 cells, colocalizing with an endosome/lysosome marker.