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 evidence that the MNK protein functions as a copper-translocating P-type ATPase in mammalian cells. The enzyme activity in membrane vesicles prepared from Chinese hamster ovary cells overexpressing MNK was ATP-dependent, correlated with the amount of MNK and followed Michaelis-Menten kinetics with respect to copper. The copper transport was observed only under reducing conditions suggesting MNK transports Cu(I). This study opens the way to detailed structure-function studies and assessment of functional MNK derived from patients with Menkes disease.
Department of Genetics, University of Melbourne, Parkville, Vic. Australia.
I
I
Voskoboinik
H
H
Brooks
S
S
Smith
P
P
Shen
J
J
Camakaris
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002352:Carrier Proteins / Q000378:metabolism*; D027682:Cation Transport Proteins; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D003300:Copper / Q000378:metabolism*; D006224:Cricetinae; D003594:Cytoplasmic Granules / Q000378:metabolism*; D017136:Ion Transport; D011993:Recombinant Fusion Proteins
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D011993:Recombinant Fusion Proteins; D003300:Copper; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases