Functional analysis of the sheep Wilson disease protein (sATP7B) in CHO cells.
In this study we investigated the function of the sheep orthologue of ATP7B (sATP7B), the protein affected in the human copper toxicosis disorder Wilson disease. Two forms of sATP7B are found in the sheep, a 'normal' form and one with an alternate N terminus, both of which were expressed in CHO-K1 cells. Cells expressing either form of sATP7B were more resistant to copper than the parental CHO-K1 cells. Subcellular localisation studies showed that both forms of sATP7B were similarly located in the trans-Golgi network (TGN). When the extracellular copper concentration was increased, each form of sATP7B redistributed to a punctate, vesicular compartment that extended throughout the cytoplasm. Both forms of sATP7B recycled to the perinuclear location within one hour when the cells were subsequently incubated in basal medium. After treatment of cells with bafilomycin A1 sATP7B accumulated in cytoplasmic vesicles, implying that ATP7B continuously recycles via the endocytic pathway. These results suggest that both forms of sATP7B are functional copper-transport proteins and that the intracellular location and trafficking of the sheep protein within the cell also appears normal.
Lockhart
P J
PJ
Centre for Cellular and Molecular Biology, School of Biological and Chemical Sciences, Deakin University, Burwood/Australia.
Mercer
J F
JF
D000251:Adenosine Triphosphatases / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016466:CHO Cells; D027682:Cation Transport Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology; D000073840:Copper-Transporting ATPases; D006224:Cricetinae; D022162:Cytoplasmic Vesicles / Q000737:chemistry / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000502:physiology; D006527:Hepatolenticular Degeneration / Q000235:genetics* / Q000378:metabolism; D018942:Macrolides; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D012756:Sheep; D014162:Transfection; D021601:trans-Golgi Network / Q000737:chemistry / Q000378:metabolism
D000900:Anti-Bacterial Agents; D027682:Cation Transport Proteins; D004791:Enzyme Inhibitors; D018942:Macrolides; D003300:Copper; C040929:bafilomycin A1; D000251:Adenosine Triphosphatases; C000612464:ATP7B protein, human; D000073840:Copper-Transporting ATPases