Sharon La Fontaine,a James Camakaris,b and Julian Mercera aStrategic Research Centre for Molecular and Medical Research and School of Life and Environmental Sciences, Deakin University, Burwood, VIC. 3125, Australia bDepartment of Genetics, The University of Melbourne, Parkville, VIC. 3010, Australia

Mammals have two transmembrane copper transporting ATPases, which show a high degree of homology and play crucial roles in copper homeostasis in various tissues including the brain (La Fontaine and Mercer, 2007; Lutsenko et al., 2007). They catalyse transport of copper across membranes and can function in both the delivery of copper to copper-dependent enzymes and proteins and in the efflux of copper from cells. Copper is essential and potentially toxic and these transporters are pivotal in maintaining copper homeostasis in individual tissues and in the whole organism. ATP7A encodes the Menkes copper transporter whilst ATP7B encodes the Wilson copper transporter. Severe neurological symptoms arise from a deficiency of either transporter. Mutations in ATP7A lead to Menkes disease (OMIM 309400), which has serious neurological symptoms resulting from severe copper deficiency, whilst mutations in ATP7B lead to Wilson disease (OMIM 277900) where hepatic and neurological symptoms are due to copper toxicosis (La Fontaine and Mercer, 2007; Lutsenko

et al., 2007). The function of these transporters is largely regulated by their sub-cellular localisation. The distribution, developmental changes, and function of these copper transporters in the brain are discussed in this chapter.