Cellular distribution of copper to superoxide dismutase involves scaffolding by membranes

• Published in: Proceedings of the National Academy of Sciences - PNAS 2013-12, Vol.110 (51), p.20491-20496
• Main Authors: Pope, Christopher R., De Feo, Christopher J., Unger, Vinzenz M.
• Format: Article
• Language: English
• Subjects: Biological Sciences; Biological Transport, Active - physiology; Cell membranes; Copper; Copper - metabolism; Cytosol - metabolism; Enzyme Activation - physiology; Freight; Genetic Complementation Test; Humans; Intracellular Membranes - metabolism; Lipid Bilayers - metabolism; Lipids; Liposomes; Membranes; Microbiology; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; P branes; Proteins; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Superoxide Dismutase - genetics; Superoxide Dismutase - metabolism; Superoxide Dismutase-1; Superoxides; T tests; Yeast; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1309820110

Efficient delivery of copper ions to specific intracellular targets requires copper chaperones that acquire metal cargo through unknown mechanisms. Here we demonstrate that the human and yeast copper chaperones (CCS) for superoxide dismutase 1 (SOD1), long thought to exclusively reside in the cytosol and mitochondrial intermembrane space, can engage negatively charged bilayers through a positively charged lipid-binding interface. The significance of this membrane-binding interface is established through SOD1 activity and genetic complementation studies in Saccharomyces cerevisiae , showing that recruitment of CCS to the membrane is required for activation of SOD1. Moreover, we show that a CCS:SOD1 complex binds to bilayers in vitro and that CCS can interact with human high affinity copper transporter 1. Shifting current paradigms, we propose that CCS-dependent copper acquisition and distribution largely occur at membrane interfaces and that this emerging role of the bilayer may reflect a general mechanistic aspect of cellular transition metal ion acquisition.