| Modification Notes |
The activity of a diverse subset of enzymes relies on the essential nutrient copper. Copper uptake requires tight regulation to ensure that sufficient copper is present in the cell to drive vital cellular processes, while avoiding the accumulation of copper to toxic levels. In Saccharomyces cerevisiae, copper regulation involves several proteins. Fre1, a surface reductase, reduces and mobilizes copper outside the cell, while the Ctr1 and Ctr3 proteins function as copper transport proteins within the plasma membrane. Regulation of these proteins occurs at the transcriptional level. Cup1, a metallothionein-like protein, binds copper and protects S. cerevisiae from copper poisoning. Ace1 activates CUP1 transcription in response to copper ions. Heat shock transcription factor also activates CUP1. |