Copper-mediated homo-dimerisation for the HAH1 metallochaperone.

The HAH1 metallochaperone is a key protein implicated in copper homeostasis in human cells. Using as solid-phase based assay completed with Biacore studies, we provided evidence that HAH1 forms homo-dimers in the presence of copper. Biacore analysis allowed us to determine the kinetic parameters of this interaction, characterised by an apparent affinity constant of 6muM. Moreover, we demonstrated that copper-loaded HAH1 interacts independently with each of the six individual metal-binding domains of the copper-translocating Menkes ATPase. Finally, the homo-dimerisation of the metallochaperone was confirmed in living cells by using fluorescence resonance energy transfer. Results have been discussed in the context of intracellular copper control.