ATOX1

Multifunctional copper-sensing protein that operates both as a cytosolic copper chaperone and as a copper-dependent transcription factor. Essential for maintaining cellular copper homeostasis and linking copper distribution to redox balance, signal transduction, and gene regulation. In the cytosol, transfers copper to the copper-transporting ATPase ATP7A at the trans-Golgi network, which is required for activation of secretory copper enzymes including lysyl oxidase (LOX) and SOD3. This chaperone function is essential for full SOD3 and LOX enzymatic activity. Acts as a copper-dependent transcription factor. Upon copper binding, translocates to the nucleus where it binds specific promoter elements and regulates transcription of genes involved in cell proliferation, oxidative stress defense, and extracellular matrix remodeling. Activates expression of target genes including CCND1, SOD3 and NCF1, thereby linking cellular copper status to gene expression programs controlling growth and redox homeostasis..

Function from UniProtKB (O00244), read 2026-09-23. CC BY 4.0.