title: Conservation of copper-transporting P(IB)-type ATPase function.
abstract: Copper-transporting P(IB)-type ATPases are highly conserved, and while unicellular eukaryotes and invertebrates have only one, a gene duplication has occurred during vertebrate evolution. Copper-induced trafficking of mammalian ATP7A and ATP7B from the trans-Golgi Network towards the plasma membrane is critical for their role in copper homeostasis. In polarized epithelial cells ATP7A and ATP7B traffic towards the basolateral and apical membranes respectively. We examined the localization and function of DmATP7, the single Drosophila melanogaster orthologue, in cultured D. melanogaster and mammalian cells to explore the conservation of P(IB)-type ATPase function. Comparative genomic analysis demonstrated motifs involved in basolateral targeting and retention of ATP7A were conserved in DmATP7, whereas ATP7B targeting motifs were not. DmATP7 expression was able to correct the copper hyper-accumulation phenotype of cultured fibroblasts from a Menkes disease patient expressing a null ATP7A allele. DmATP7 was able to transport copper to the cupro-enzyme tyrosinase and under elevated copper conditions DmATP7 was able to traffic towards the plasma membrane and efflux copper, essentially phenocopying ATP7A. When expressed in polarized Madin-Darby Canine Kidney cells, DmATP7 translocated towards the basolateral membrane when exposed to elevated copper, similar to ATP7A. These results demonstrate DmATP7 is able to functionally compensate for the absence of ATP7A, with important trafficking motifs conserved in these distantly related orthologues.
authors.affiliation: Department of Genetics, The University of Melbourne, Melbourne, VIC 3010, Australia.
authors.forename: Adam
authors.initials: A
authors.lastname: Southon
authors.forename: Nickless
authors.initials: N
authors.lastname: Palstra
authors.forename: Nicholas
authors.initials: N
authors.lastname: Veldhuis
authors.forename: Ann
authors.initials: A
authors.lastname: Gaeth
authors.forename: Charles
authors.initials: C
authors.lastname: Robin
authors.forename: Richard
authors.initials: R
authors.lastname: Burke
authors.forename: James
authors.initials: J
authors.lastname: Camakaris
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003300:Copper / Q000378:metabolism*; D000073840:Copper-Transporting ATPases; D004285:Dogs; D004331:Drosophila melanogaster / Q000201:enzymology; D006801:Humans; D007706:Menkes Kinky Hair Syndrome / Q000235:genetics / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000378:metabolism
chemical_list: C497836:ATP7 protein, Drosophila; D027682:Cation Transport Proteins; D003300:Copper; D014442:Monophenol Monooxygenase; D000251:Adenosine Triphosphatases; D000073840:Copper-Transporting ATPases