Genes regulating copper metabolism.

The metabolism of Cu is intimately linked with its nutrition. From gut to enzymes, Cu bioavailability to key enzymes and other components operates through a complex mechanism that uses transport proteins as well as small molecular weight ligands. Steps in Cu transport through the blood, absorption by cells, and incorporation into enzymes are slowly being understood. Cloning and sequencing of the genes for Menkes disease and Wilson disease has shown that membrane-bound enzymes analogous to Cu-ATPases in prokaryotes are equally important to Cu transport and homeostasis in mammalian cells. The primary structure of the mammalian Cu-ATPases has been deduced from cDNAs from tissues and organs. It now appears that mammalian Cu-ATPase have tissue and developmental specificity. In this review, we will focus on the Cu-ATPase that has been identified with Menkes disease. An emphasis will be placed on the existence of multiple forms of the ATPase and some indication as to how the different isoforms befit their role in the normal physiology of copper, specifically transmembrane transport and maintenance of a favorable internal cellular environment.