ATP-dependent transporter that catalyzes the transport of a broad-spectrum of porphyrins from the cytoplasm to the extracellular space through the plasma membrane or into the vesicle lumen ( , ). May also function as an ATP-dependent importer of porphyrins from the cytoplasm into the mitochondria, in turn may participate in the de novo heme biosynthesis regulation and in the coordination of heme and iron homeostasis during phenylhydrazine stress ( , ). May also play a key role in the early steps of melanogenesis producing PMEL amyloid fibrils . In vitro, it confers to cells a resistance to toxic metal such as arsenic and cadmium and against chemotherapeutics agent such as 5-fluorouracil, SN-38 and vincristin ( ). In addition may play a role in the transition metal homeostasis (By similarity).
Subcellular locations: Cell membrane, Mitochondrion outer membrane, Endoplasmic reticulum membrane, Golgi apparatus membrane, Endosome membrane, Lysosome membrane, Late endosome membrane, Early endosome membrane, Secreted, Extracellular exosome, Mitochondrion, Endosome, Multivesicular body membrane, Melanosome membrane
Present in the membrane of mature erythrocytes and in exosomes released from reticulocytes during the final steps of erythroid maturation . Traffics from endoplasmic reticulum to Golgi during its glycans's maturation, therefrom is first targeted to the plasma membrane, and is rapidly internalized through endocytosis to be distributed to the limiting membrane of multivesicular bodies and lysosomes ( ). Localized on the limiting membrane of early melanosomes of pigment cells . Targeted to the endolysosomal compartment (By similarity).
Widely expressed. High expression is detected in the retinal epithelium (, ). Expressed in mature erythrocytes .