Copper is an essential element in eukaryotic organisms. Due to facile redox chemistry at moderate potentials, it functions at the active sites of many critical enzymes involved in a wide variety of processes, including neurotransmitter and neuropeptide hormone biosynthesis, biogenic amine metabolism and connective tissue formation, pigmentation, respiration, and antioxidant defense. New findings have linked certain cancers to copper mediated enzyme activity, for example the observation that the expression of the cuproenzyme PAM in endocrine tumors mediates tumor growth. Another intriguing link of importance to cancer therapy, is the recruitment of the CTR1 high affinity copper transporter in the uptake of cis-platin into cells by a presently unknown mechanism. Because copper is both essential and potentially toxic, cells have evolved complex molecular machinery to maintain levels within a narrow range of concentration, and failure to achieve liomeostasis results in diseases related to either Cu deficiency or excess which include those involving genetic mutations in the copper transporting ATPases, ATP7A (Menkes disease) and ATP7B (Wilson disease). Important consequences of aberrant copper homeostasis have also been implicated in neurodegenerative disorders, and in the pathology of amyloid plaque formation in Alzheimers. Therefore, the study of copper uptake, transport and trafficking is of great importance to human health. In eukaryotes, copper is imported by the membrane associated high affinity transporter CTR1, and thence distributed to target proteins via metallochaperone shuttles. An important tenet of copper homeostasis is the hypothesis that CTR1 hands off copper to the chaperones which in turn transport the metal to its sites of action. However, the interaction of CTR1 with chaperones has not yet been experimentally verified. Project 2 of the PPG will therefore leverage recent advances in the structural biology of hCTRl to investigate (i) the mode of copper binding to CTR1, (ii) the interaction of CTR1 with the chaperone hCCS, and (iii) the mechanisms by which chaperones and ATPases interact with and transfer copper to their target cuproenzymes. The technique of selenium-labeling coupled to X-ray absorption spectroscopy (developed in the last grant period) will be used extensively in these studies.

Public Health Relevance

Metal ions such as iron and copper play vital roles in many aspects of human health. Some disorders arise from defects in genes for metal transport proteins (Menkes and Wilson diseases), while others are now being linked to aberrant pathways of metal ion homeostasis (Alzheimers, ALS, ataxias, certain types of cancers). This project will elucidate these aberrant pathways using novel biophysical approaches developed by the PI.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Program Projects (P01)
Project #
5P01GM067166-10
Application #
8530243
Study Section
Special Emphasis Panel (ZRG1-CB-L)
Project Start
Project End
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
10
Fiscal Year
2013
Total Cost
$237,788
Indirect Cost
Name
Johns Hopkins University
Department
Type
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Gupta, Arnab; Schell, Michael J; Bhattacharjee, Ashima et al. (2016) Myosin Vb mediates Cu+ export in polarized hepatocytes. J Cell Sci 129:1179-89
Krishnamoorthy, Lakshmi; Cotruvo Jr, Joseph A; Chan, Jefferson et al. (2016) Copper regulates cyclic-AMP-dependent lipolysis. Nat Chem Biol 12:586-92
Kline, Chelsey D; Gambill, Benjamin F; Mayfield, Mary et al. (2016) pH-regulated metal-ligand switching in the HM loop of ATP7A: a new paradigm for metal transfer chemistry. Metallomics 8:729-33
Clifford, Rebecca J; Maryon, Edward B; Kaplan, Jack H (2016) Dynamic internalization and recycling of a metal ion transporter: Cu homeostasis and CTR1, the human Cu⁺ uptake system. J Cell Sci 129:1711-21
Hamilton, James P; Koganti, Lahari; Muchenditsi, Abigael et al. (2016) Activation of liver X receptor/retinoid X receptor pathway ameliorates liver disease in Atp7B(-/-) (Wilson disease) mice. Hepatology 63:1828-41
Dmitriev, Oleg Y; Lutsenko, Svetlana; Muyldermans, Serge (2016) Nanobodies as Probes for Protein Dynamics in Vitro and in Cells. J Biol Chem 291:3767-75
Braiterman, Lelita T; Gupta, Arnab; Chaerkady, Raghothama et al. (2015) Communication between the N and C termini is required for copper-stimulated Ser/Thr phosphorylation of Cu(I)-ATPase (ATP7B). J Biol Chem 290:8803-19
Braiterman, Lelita T; Murthy, Amrutha; Jayakanthan, Samuel et al. (2014) Distinct phenotype of a Wilson disease mutation reveals a novel trafficking determinant in the copper transporter ATP7B. Proc Natl Acad Sci U S A 111:E1364-73
Nyasae, Lydia K; Schell, Michael J; Hubbard, Ann L (2014) Copper directs ATP7B to the apical domain of hepatic cells via basolateral endosomes. Traffic 15:1344-65
Malinouski, Mikalai; Hasan, Nesrin M; Zhang, Yan et al. (2014) Genome-wide RNAi ionomics screen reveals new genes and regulation of human trace element metabolism. Nat Commun 5:3301

Showing the most recent 10 out of 65 publications