The trace element copper (Cu) is an essential cofactor for critical life processes that include mitochondrial oxidative phosphorylation, iron absorption, reactive oxygen detoxification, peptide hormone biogenesis, connective tissue maturation and cellular signaling. Dietary Cu limitation, defects in the Cu acquisition machinery, or the inability to adapt to Cu deficiency gives rise to pathophysiological states in specific cells and tissues including iron deficiency anemia, neuronal and cognitive dysfunction, connective tissue defects, hypertrophic cardiomyopathy and gestational lethality. Importantly, Cu chelators are used to treat patients with devastating Cu overload disease, and are being developed for use in cancer chemotherapy. While Cu acquisition, and appropriate adaptive responses to Cu limitation are critical for human development and health, we know little about how cells adapt to Cu limitation through increased Cu import or critical regulatory changes. This application details experiments to decipher two fundamentally important gaps in our knowledge of the components involved in Cu acquisition and the mechanisms by which cells adapt to Cu-limitation. We will exploit the powerful fungal model system, Cryptococcus neoformans, which has a strong reliance on Cu- dependent metabolism for its growth, and which has a rich biology of genes whose expression is regulated by Cu-deficiency. First, we will elucidate the role that a new extracellular protein, Bim1, plays in Cu acquisition. We will test the hypothesis that Bim1 serves as an extracellular Cu ligand that functions in concert with the Ctr1-mediated plasma membrane Cu+ import machinery and that Bim1 is critical for cell growth and survival in a naturally occurring Cu-limiting environment. These experiments will validate the first extracellular Cu-ligand in eukaryotic Cu-uptake, filling a gap in our understanding of how organisms acquire this essential trace element. Second, we will decipher how under Cu-limiting conditions, expression of the abundant Sod1 Cu-dependent protein is extinguished, the physiological role this plays in prioritizing Cu to proteins critical for normal growth, and how cells adapt to loss of Sod1 through changes in the localization and synthesis of other proteins via cellular translation reprogramming. Together, these studies will advance new concepts for how cells acquire the essential metal ion Cu, invoke adaptive responses to Cu limitation and regulate these processes for normal cell growth, function and health.

Public Health Relevance

The trace element copper is critical to support the activity of numerous enzymes and physiological processes and is thus essential for normal growth, development and health in humans. Copper deficiency can occur when dietary supplies are limiting, through defects in the function of the copper import machinery or through the inability to properly adjust to accommodate low copper levels. This project will elucidate how organisms acquire copper and implement proper adaptive pathways when copper is limiting to prevent growth defects.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM041840-30
Application #
9904660
Study Section
Macromolecular Structure and Function A Study Section (MSFA)
Program Officer
Melillo, Amanda A
Project Start
1989-04-01
Project End
2023-03-31
Budget Start
2020-04-01
Budget End
2021-03-31
Support Year
30
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Duke University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Romero, Antonia M; Martínez-Pastor, Mar; Du, Gang et al. (2018) Phosphorylation and Proteasome Recognition of the mRNA-Binding Protein Cth2 Facilitates Yeast Adaptation to Iron Deficiency. MBio 9:
Garcia-Santamarina, Sarela; Festa, Richard A; Smith, Aaron D et al. (2018) Genome-wide analysis of the regulation of Cu metabolism in Cryptococcus neoformans. Mol Microbiol 108:473-494
Logeman, Brandon L; Thiele, Dennis J (2018) Reconstitution of a thermophilic Cu+ importer in vitro reveals intrinsic high-affinity slow transport driving accumulation of an essential metal ion. J Biol Chem 293:15497-15512
Yang, Dong-Hoon; Jung, Kwang-Woo; Bang, Soohyun et al. (2017) Rewiring of Signaling Networks Modulating Thermotolerance in the Human Pathogen Cryptococcus neoformans. Genetics 205:201-219
Garcia-Santamarina, Sarela; Uzarska, Marta A; Festa, Richard A et al. (2017) Cryptococcus neoformans Iron-Sulfur Protein Biogenesis Machinery Is a Novel Layer of Protection against Cu Stress. MBio 8:
García-Santamarina, Sarela; Thiele, Dennis J (2015) Copper at the Fungal Pathogen-Host Axis. J Biol Chem 290:18945-53
Allensworth, Jennifer L; Evans, Myron K; Bertucci, François et al. (2015) Disulfiram (DSF) acts as a copper ionophore to induce copper-dependent oxidative stress and mediate anti-tumor efficacy in inflammatory breast cancer. Mol Oncol 9:1155-68
Öhrvik, Helena; Thiele, Dennis J (2015) The role of Ctr1 and Ctr2 in mammalian copper homeostasis and platinum-based chemotherapy. J Trace Elem Med Biol 31:178-82
Sun, Tian-Shu; Ju, Xiao; Gao, Hui-Ling et al. (2014) Reciprocal functions of Cryptococcus neoformans copper homeostasis machinery during pulmonary infection and meningoencephalitis. Nat Commun 5:5550
Ohrvik, Helena; Thiele, Dennis J (2014) How copper traverses cellular membranes through the mammalian copper transporter 1, Ctr1. Ann N Y Acad Sci 1314:32-41

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