title: Characterization of ATP7A missense mutants suggests a correlation between intracellular trafficking and severity of Menkes disease.
abstract: Menkes disease (MD) is caused by mutations in ATP7A, encoding a copper-transporting P-type ATPase which exhibits copper-dependent trafficking. ATP7A is found in the Trans-Golgi Network (TGN) at low copper concentrations, and in the post-Golgi compartments and the plasma membrane at higher concentrations. Here we have analyzed the effect of 36 ATP7A missense mutations identified in phenotypically different MD patients. Nine mutations identified in patients with severe MD, virtually eliminated ATP7A synthesis, in most cases due to aberrant RNA splicing. A group of 21 predominantly severe mutations led to trapping of the protein in TGN and displayed essentially no activity in a yeast-based functional assay. These were predicted to inhibit the catalytic phosphorylation of the protein. Four mutants showed diffuse post-TGN localization, while two displayed copper dependent trafficking. These six variants were identified in patients with mild MD and typically displayed activity in the yeast assay. The four post-TGN located mutants were presumably affected in the catalytic dephosphorylation of the protein. Together these results indicate that the severity of MD correlate with cellular localization of ATP7A and support previous studies indicating that phosphorylation is crucial for the exit of ATP7A from TGN, while dephosphorylation is crucial for recycling back to TGN.
authors.affiliation: Applied Human Genetics, Kennedy Center, Department of Clinical Genetics, Copenhagen University, Rigshospitalet, Glostrup, Denmark.|Section of Neurobiology, Biomedicine group, Institute of Medicine and Health Technology, Aalborg University, Aalborg, Denmark.
authors.forename: Tina
authors.initials: T
authors.lastname: Skjørringe
authors.affiliation: Department of Biology, August Krogh Building, University of Copenhagen, Universitetsparken 13, DK-2100, Copenhagen OE, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Amstrup Pedersen
authors.affiliation: Applied Human Genetics, Kennedy Center, Department of Clinical Genetics, Copenhagen University, Rigshospitalet, Glostrup, Denmark.
authors.forename: Sidsel
authors.initials: S
authors.lastname: Salling Thorborg
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMKIN, Aarhus University, Department of Molecular Biology, Gustav Wieds Vej 10C, DK-8000, Aarhus C, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Nissen
authors.affiliation: Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark.|Department of Experimental Medical Science, Lund University, Sölvegatan 19, SE-221 84, Lund, Sweden.
authors.forename: Pontus
authors.initials: P
authors.lastname: Gourdon
authors.affiliation: Applied Human Genetics, Kennedy Center, Department of Clinical Genetics, Copenhagen University, Rigshospitalet, Glostrup, Denmark. Lisbeth.birk.moeller@regionh.dk.|Department of Science, Systems and Models, Roskilde University, Universitetsvej 1, DK-4000, Roskilde, Denmark. Lisbeth.birk.moeller@regionh.dk.
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Birk Møller
mesh_terms: D000483:Alleles; D017398:Alternative Splicing; D019943:Amino Acid Substitution; D015415:Biomarkers; D003300:Copper / Q000378:metabolism; D000073840:Copper-Transporting ATPases / Q000235:genetics* / Q000378:metabolism*; D005347:Fibroblasts; D005455:Fluorescent Antibody Technique; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D007706:Menkes Kinky Hair Syndrome / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism*; D008954:Models, Biological; D020125:Mutation, Missense; D010641:Phenotype; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex; D021381:Protein Transport; D059748:Proteolysis; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D003300:Copper; D046988:Proteasome Endopeptidase Complex; C081184:ATP7A protein, human; D000073840:Copper-Transporting ATPases