Copper Transport Mechanisms and Protein Interactions

Copper is an essential micronutrient that plays a pivotal role in enzymatic redox reactions, energy production and connective tissue synthesis. To harness its biological utility while avoiding toxicity, cells orchestrate a finely tuned network of transport proteins and chaperones that coordinate uptake, intracellular delivery and export of copper ions. Plasma membrane importers such as CTR1 facilitate high-affinity uptake of copper(I), which is then bound by small cytosolic chaperones. These copper chaperones, typified by Atox1 in mammals and ATX1 in plants, guide the metal safely through the cytoplasm to P-type ATPases. The P1B-type ATPases, represented by ATP7A and ATP7B in humans and by CopA homologues in bacteria and archaea, harness the energy of ATP hydrolysis to translocate copper across intracellular membranes or export it from cells. Each ATPase contains multiple metal-binding domains (MBDs) that both receive copper from chaperones and regulate catalytic activity and trafficking. Dysregulation of any component in this network underlies disorders such as Wilson and Menkes diseases, and emerging work implicates copper transport in immune defence and cancer drug resistance. Recent structural, biophysical and computational studies are now unravelling the dynamic interplay of domains and residues that ensure specificity, directionality and safety of copper handling.

Research from Nature Portfolio

Recent structural analyses combining cryo-electron microscopy and molecular dynamics simulations have elucidated the conformational cycle of a eukaryotic P1B-1 ATPase. These studies reveal that the MBD immediately preceding the ATPase core remodels the ion-uptake site to prepare for copper binding, while a second upstream MBD functions as a copper delivery module. Critical tyrosine, asparagine and serine residues in the transmembrane helices position copper-binding side chains to facilitate uptake, coordination and release, thereby reconciling previously conflicting mechanistic models. In parallel, high-resolution nuclear magnetic resonance and biophysical characterisation of a plant-specific copper chaperone have demonstrated that its extended C-terminal region is intrinsically disordered yet indispensable for stabilising dimer formation. The disordered segment promotes chaperone dimerisation in both apo and copper-loaded states, with specific residues mediating inter-monomer contacts without perturbing the core metal-binding site. Computational corroboration of key stabilising interactions underscores the complexity of chaperone assembly and its potential regulatory significance.

Copper Transport Mechanisms and Protein Interactions publication trend

The graph below shows the total number of articles in copper transport mechanisms and protein interactions across all publications each year (not limited to Nature Index journals).

Technical terms

Copper chaperone: a soluble protein that binds copper ions and delivers them to specific enzymes or transporters, preventing free-copper toxicity.

P-type ATPase: a membrane-bound enzyme that utilises ATP hydrolysis to transport metal ions across lipid bilayers, maintaining cellular homeostasis.

Metal-binding domain (MBD): a protein region containing conserved motifs that coordinate metal ions, often modulating activity, stability and protein–protein interactions.

Copper homeostasis: the ensemble of cellular processes that regulate copper import, distribution and export to balance essential biochemical functions and avoid metal-induced damage.

References

1. Diverse roles of the metal binding domains and transport mechanism of copper transporting P-type ATPases. Nature Communications (2024).
2. Structure and dimerization properties of the plant-specific copper chaperone CCH. Scientific Reports (2024).
3. The six metal binding domains in human copper transporter, ATP7B: molecular biophysics and disease-causing mutations. BioMetals (2017).
4. Copper Homeostasis at the Host-Pathogen Interface*. Journal of Biological Chemistry (2012).
5. The metal chaperone Atox1 regulates the activity of the human copper transporter ATP7B by modulating domain dynamics. Journal of Biological Chemistry (2017).
6. Structure of the Two Transmembrane Cu+ Transport Sites of the Cu+-ATPases*. Journal of Biological Chemistry (2008).