Feline leukemia virus subgroup C receptor-related protein 1 (FLVCR1)

Isoform 1: Heme transporter that exports cytoplasmic heme. It can also export coproporphyrin and protoporphyrin IX, which are both intermediate goods in the heme biosynthetic pathway.

Doesn't export bilirubin. Heme export depends upon the presence of HPX and is needed to maintain free heme balance, protecting cells from heme toxicity.