Copper-sensing transcription factor that regulates copper uptake by transactivation of Ctr3, a high affinity copper permease. Binds to the palindromic UAS sequence 5'-TGTTGCTCANNNNAGAGCAACT-3'. Also transactivates Sod2, a mitochondrial manganese superoxide dismutase through the palindromic UAS sequence 5'-GTTTGCTCA-3' with 352 bp separating the two inverted repeats. Loss of function indirectly leads to rearrangement of mitochondrial DNA associated with senescence in wild-type strains.