The long-term goal of these studies is to understand the fundamental mechanisms that regulate the concentration of copper in human cells. Copper plays an essential role in human physiology and is required for embryonic development, respiration, neurotransmitter biosynthesis, and other important physiological processes. Human copper-transporting ATPases ATP7A and ATP7B play a central role in the regulation of intracellular copper. Mutations in these transporters result in the severe metabolic disorders, Menkes disease and Wilson's disease, respectively. Recent studies also suggest that ATP7A (Menkes disease protein, MNKP) and ATP7B (Wilson's disease protein, WNDP) are involved in cellular resistance to platinumbased chemotherapeutic drugs, and therefore could be important pharmacological targets in cancer treatment. Despite the essential role of MNKP and WNDP in human physiology, our knowledge of how these ATP-driven transporters regulate intracellular copper is extremely limited. In the proposed series of experiments, a unique set of biochemical tools established by the PI's laboratory is utilized to dissect specific molecular mechanisms that control the function and regulation of WNDP and MNKP in cells.
Four specific aims are proposed. The first objective is to generate a comprehensive picture of copper-dependent regulation of WNDP and MNKP by characterizing the functional roles of the multiple metal-binding sites in the N-terminal domain of these proteins. The second goal is to obtain structural information necessary for an understanding of nucleotide binding by WNDP and MNKP and for the development of specific inhibitors for these transporters. Thirdly, the role of a recently discovered protein Murr1 in the function and regulation of WNDP will be determined using a combination of biochemical and cell biological approaches. The final objective is to dissect the molecular mechanism of the MNKP/WNDP-related cisplatin resistance. These studies will yield important mechanistic information about the regulation of copper in human cells and will contribute to a better understanding and treatment of disorders associated with copper misbalance.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
7R01DK071865-05
Application #
7648249
Study Section
Biochemistry and Biophysics of Membranes Study Section (BBM)
Program Officer
Serrano, Jose
Project Start
2005-08-01
Project End
2010-09-19
Budget Start
2009-08-01
Budget End
2010-09-19
Support Year
5
Fiscal Year
2009
Total Cost
$312,404
Indirect Cost
Name
Johns Hopkins University
Department
Physiology
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
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Jayakanthan, Samuel; Braiterman, Lelita T; Hasan, Nesrin M et al. (2017) Human copper transporter ATP7B (Wilson disease protein) forms stable dimers in vitro and in cells. J Biol Chem 292:18760-18774
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Hatori, Yuta; Yan, Ye; Schmidt, Katharina et al. (2016) Neuronal differentiation is associated with a redox-regulated increase of copper flow to the secretory pathway. Nat Commun 7:10640
Lutsenko, Svetlana (2014) Modifying factors and phenotypic diversity in Wilson's disease. Ann N Y Acad Sci 1315:56-63
Hatori, Yuta; Lutsenko, Svetlana (2013) An expanding range of functions for the copper chaperone/antioxidant protein Atox1. Antioxid Redox Signal 19:945-57
Polishchuk, Roman; Lutsenko, Svetlana (2013) Golgi in copper homeostasis: a view from the membrane trafficking field. Histochem Cell Biol 140:285-95
Hasan, Nesrin M; Gupta, Arnab; Polishchuk, Elena et al. (2012) Molecular events initiating exit of a copper-transporting ATPase ATP7B from the trans-Golgi network. J Biol Chem 287:36041-50
Schushan, Maya; Bhattacharjee, Ashima; Ben-Tal, Nir et al. (2012) A structural model of the copper ATPase ATP7B to facilitate analysis of Wilson disease-causing mutations and studies of the transport mechanism. Metallomics 4:669-78

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