ATP-DEPENDENT COPPER TRANSPORT BY THE MENKES PROTEIN IN MEMBRANE-VESICLES ISOLATED FROM CULTURED CHINESE-HAMSTER OVARY CELLS

The Menkes (MNK) protein is a vital component of copper homeostasis in mammalian cells. In this paper we provide the first biochemical evide nce that the MNK protein functions as a copper-translocating P-type AT Pase in mammalian cells. The enzyme activity in membrane vesicles prep ared from Chinese hamster ovary cells overexpressing MNK was ATP-depen dent, correlated with the amount of MNK and followed Michaelis-Menten kinetics with respect to copper. The copper transport,vas observed onl y under reducing conditions suggesting MNK transports Cu(I), This stud y opens the way to detailed structure function studies and assessment of functional MNK derived from patients with Menkes disease. (C) 1998 Federation of European Biochemical Societies.