Human glutaredoxin-1 can transfer copper to isolated metal binding domains of the P-1B-type ATPase, ATP7B

• Type of Material: Article
• Authors: Shadi Maghool, La Trobe University; Sharon La Fontaine, Deakin University; Blaine Roberts, Emory University; Ann H. Kwan, University of Sydney; Megan J. Maher, La Trobe University
• Language: English
• Date: 2020-03-05
• Publisher: Nature Publishing Group
• Publication Version: Final Published Version
• Copyright Statement: © 2020 Springer Nature Limited
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41598-020-60953-z
• Title of Journal or Parent Work: Scientific Reports
• Volume: 10
• Issue: 1
• Start Page: 4157
• End Page: 4157
• Grant/Funding Information: This study was funded by the Australian Research Council (DP140102746 to MJM). SM was supported by an Australian Government Research Training Program Scholarship.; BRR was supported by a NHMRC Dementia Leadership Fellowship (APP1138673). The support of the Florey Neuroproteomics facility and Adam Gunn for assistance in size exclusion ICP-MS data collection and analysis are also acknowledged.
• Keywords: In-vivo; N-terminal domain; Menkes; Chaperone ATOX1; Transport; Science & Technology; Wilsons disease protein; Multidisciplinary Sciences; Glutathione; Metallochaperone; NMR Solution structure; Crystal structure; Science & Technology - Other Topics
• Research Categories: Environmental Sciences; Biology, Neuroscience; Biology, Genetics; Chemistry, Biochemistry

Abstract

Intracellular copper (Cu) in eukaryotic organisms is regulated by homeostatic systems, which rely on the activities of soluble metallochaperones that participate in Cu exchange through highly tuned protein-protein interactions. Recently, the human enzyme glutaredoxin-1 (hGrx1) has been shown to possess Cu metallochaperone activity. The aim of this study was to ascertain whether hGrx1 can act in Cu delivery to the metal binding domains (MBDs) of the P1B-type ATPase ATP7B and to determine the thermodynamic factors that underpin this activity. hGrx1 can transfer Cu to the metallochaperone Atox1 and to the MBDs 5-6 of ATP7B (WLN5-6). This exchange is irreversible. In a mixture of the three proteins, Cu is delivered to the WLN5-6 preferentially, despite the presence of Atox1. This preferential Cu exchange appears to be driven by both the thermodynamics of the interactions between the proteins pairs and of the proteins with Cu(I). Crucially, protein-protein interactions between hGrx1, Atox1 and WLN5-6 were detected by NMR spectroscopy both in the presence and absence of Cu at a common interface. This study augments the possible activities of hGrx1 in intracellular Cu homeostasis and suggests a potential redundancy in this system, where hGrx1 has the potential to act under cellular conditions where the activity of Atox1 in Cu regulation is attenuated.