ABCB6
Developmental stage
Highly expressed in fetal liver.
Domain
Contains two independently folding units, the N-terminal transmembrane domain (residues 1-205) and the ABC-core domain (206-842) are respectively responsible for the lysosomal targeting and the ATPase activity.
Function
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 (PubMed:17661442, PubMed:23792964, PubMed:27507172, PubMed:33007128). 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 (PubMed:10837493, PubMed:17006453, PubMed:23792964, PubMed:33007128). May also play a key role in the early steps of melanogenesis producing PMEL amyloid fibrils (PubMed:29940187). 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 (PubMed:21266531, PubMed:25202056, PubMed:31053883). In addition may play a role in the transition metal homeostasis (By similarity).
Involvement in disease
Microphthalmia/Coloboma 7
MCOPCB7
A disorder of eye formation, ranging from small size of a single eye to complete bilateral absence of ocular tissues. Ocular abnormalities like opacities of the cornea and lens, scaring of the retina and choroid, and other abnormalities may also be present. Ocular colobomas are a set of malformations resulting from abnormal morphogenesis of the optic cup and stalk, and the fusion of the fetal fissure (optic fissure).
None
The disease is caused by variants affecting the gene represented in this entry.
Dyschromatosis universalis hereditaria 3
DUH3
An autosomal dominant pigmentary genodermatosis characterized by a mixture of hyperpigmented and hypopigmented macules distributed randomly over the body, that appear in infancy or early childhood. The trunk and extremities are the dominant sites of abnormal pigmentation. Facial lesions can be seen in 50% of affected individuals, but involvement of palms and soles is unusual. Abnormalities of hair and nails have also been reported. Dyschromatosis universalis hereditaria may be associated with abnormalities of dermal connective tissue, nerve tissue, or other systemic complications.
None
The disease is caused by variants affecting the gene represented in this entry.
Pseudohyperkalemia, familial, 2, due to red cell leak
PSHK2
A dominantly inherited condition characterized by increased serum potassium levels, measured in whole-blood specimens stored at or below room temperature. This condition is not accompanied by clinical symptoms or biological signs except for borderline abnormalities of red cell shape.
None
The disease is caused by variants affecting the gene represented in this entry.
Defects in ABCB6 may be the cause of a severe porphyria. Affected individuals show higher urinary porphyrin concentrations.
Post-translational modifications
N-glycosylated.
Sequence Similarities
Belongs to the ABC transporter superfamily. ABCB family. Heavy Metal importer (TC 3.A.1.210) subfamily.
Tissue Specificity
Widely expressed. High expression is detected in the retinal epithelium (PubMed:10837493, PubMed:22226084). Expressed in mature erythrocytes (PubMed:22655043).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Mitochondrion outer membrane
- Multi-pass membrane protein
- Endoplasmic reticulum membrane
- Multi-pass membrane protein
- Golgi apparatus membrane
- Multi-pass membrane protein
- Endosome membrane
- Multi-pass membrane protein
- 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 (PubMed:22655043). 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 (PubMed:18279659, PubMed:21199866, PubMed:25627919). Localized on the limiting membrane of early melanosomes of pigment cells (PubMed:29940187). Targeted to the endolysosomal compartment (By similarity).
Alternative names
MTABC3, PRP, UMAT, ABCB6, ATP-binding cassette sub-family B member 6, ABC-type heme transporter ABCB6, Mitochondrial ABC transporter 3, P-glycoprotein-related protein, Ubiquitously-expressed mammalian ABC half transporter, Mt-ABC transporter 3