Schematic model depicting the key players involved in mammalian cellular acquisition, intracellular distribution, sensing, and mobilization of copper (Cu). ATOX1, antioxidant protein 1; Atp7A and B, copper transporting ATPaseA and B; CCO, cytochrome c oxidase; CCS, copper chaperone for SOD1; Ctr1 and 2, copper transporter 1 and 2; MT, metallothionein; SOD1, Cu/Zn- superoxide dismutase; tCtr1, truncated Ctr1.