A physiological role for Saccharomyces cerevisiae copper/zinc superoxide dismutase in copper buffering

Valeria Cizewski Culotta, Hung Dong Joh, Su Ju Lin, Kimberly Hudak Slekar, Jeffrey Strain

Research output: Contribution to journalArticlepeer-review

137 Scopus citations


The copper toxicity of yeast lacking the CUP1 metallothionein is suppressed by overexpression of the CRS4 gene. We now demonstrate that CRS4 is equivalent to SOD1, encoding copper/zinc superoxide dismutase (SOD). While overexpression of SOD1 enhanced copper resistance, a deletion of SOD1, but not SOD2 (encoding manganese SOD), conferred an increased sensitivity toward copper. This role of SOD1 in copper buffering appears unrelated to its superoxide scavenging activity, since the enzyme protected against copper toxicity in anaerobic as well as aerobic conditions. The distinct roles of SOD1 in copper and oxygen radical homeostasis could also be separated genetically: the pmr1, bsd2, and ATX1 genes that suppress oxygen toxicity in sod1 mutants failed to suppress the copper sensitivity of these cells. The Saccharomyces cerevisiae SOD1 gene is transcriptionally induced by copper and the ACE1 transactivator, and we demonstrate here that this induction of SOD1 promotes protection against copper toxicity but is not needed for the SOD1- protection against oxygen free radicals. Collectively, these findings indicate that copper/zinc SOD functions in the homeostasis of copper via mechanisms distinct from superoxide scavenging.

Original languageEnglish (US)
Pages (from-to)29991-29997
Number of pages7
JournalJournal of Biological Chemistry
Issue number50
StatePublished - Dec 15 1995

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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