The overall goal of this program is to generate a comprehensive mechanistic picture of human copper homeostasis in normal and diseased cells and tissues. Copper is an essential nutrient required for embryonic development, connective tissue formation, myelination of neurons, detoxification of radicals, and many other physiological processes. Copper deficiency is deleterious to human growth and development, yet excess copper is toxic. Dysregulation of copper homeostasis is associated with severe metabolic and neurological disorders, which may affect patients at any stage of life. In this Program Project, the mechanisms that control copper distribution in human cells and tissues will be characterized by a team of established investigators with complementary expertise in areas of structural biology, membrane transport, metal-ion coordination, cell polarity, and protein trafficking. The highly collaborative studies will address issues central to the understanding of human copper homeostasis. Specifically, the molecular mechanisms of copper uptake and export will be investigated using a combination of protein crystallization, electron microscopy, X-ray absorption spectroscopy as well as functional analysis of molecules involved in the intracellular copper trafficking (CTR1, CTR2, copper chaperones, and Cu-transporting ATPases). Factors that regulate copper transporters in epithelia will be characterized using polarized cell systems, direct transport measurements, confocal microscopy, site-directed mutagenesis, and mass-spectrometry of identified protein complexes. The physiological aspects of copper regulation in normal and diseased tissues will be investigated using animal models. The Program Project includes 5 interconnected research programs as well as the Metal Ion Core. The proposed research program will yield new information, integrate the data into a multifaceted view of human copper homeostasis, and will contribute to a better understanding of human disorders of copper metabolism. Useful shared reagents will be generated and will be made available to the biomedical community. Public Health Relevance: The PPG will address fundamental questions related to the role of copper in human biology and will employ an interdisciplinary approach to provide a detailed understanding of the molecular mechanisms of copper homeostasis in human cells. Dysregulation of copper homeostasis is a cause of several severe metabolic disorders. The proposed studies would elucidate the key aspects of copper regulation in human cells;that would facilitate the development of better therapies for copper-related disorders.