Human Copper Chaperone Atox1 Translocates to the Nucleus but does not Bind DNA In Vitro

Title:Human Copper Chaperone Atox1 Translocates to the Nucleus but does not Bind DNA In Vitro

Volume: 22 Issue: 6

Author(s): Dana Kahra, Tanumoy Mondol, Moritz S. Niemiec and Pernilla Wittung-Stafshede

Affiliation:

Keywords: Atox1, Copper chaperone, fluorescence microscopy, fluorescence spectroscopy, transcription factor.

Abstract: After Ctr1-mediated cell uptake, copper (Cu) is transported by the cytoplasmic Cu chaperone Atox1 to P_1B type ATPases ATP7A and ATP7B in the Golgi network, for incorporation into Cudependent enzymes. Atox1 is a small 68-residue protein that binds Cu in a conserved CXXC motif; it delivers Cu to target domains in ATP7A/B via direct protein-protein interactions. Specific transcription factors regulating expression of the human Cu transport proteins have not been reported although Atox1 was recently suggested to have dual functionality such that it, in addition to its cytoplasmic chaperone function, acts as a transcription factor in the nucleus. To examine this hypothesis, here we investigated the localization of Atox1 in HeLa cells using fluorescence imaging in combination with in vitro binding experiments to fluorescently labeled DNA duplexes harboring the proposed promotor sequence. We found that whereas Atox1 is present in the nucleus in HeLa cells, it does not bind to DNA in vitro. It appears that Atox1 mediates transcriptional regulation via additional (unknown) proteins.

Cite this article as:

Kahra Dana, Mondol Tanumoy, Niemiec S. Moritz and Wittung-Stafshede Pernilla, Human Copper Chaperone Atox1 Translocates to the Nucleus but does not Bind DNA In Vitro, Protein & Peptide Letters 2015; 22 (6) . https://dx.doi.org/10.2174/0929866522666150506094546