Copper transport activity of yeast Ctr1 is down-regulated via its C terminus in response to excess copper

Xiaobin Wu, Devis Sinani, Heejong Kim, Jaekwon Lee

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Copper is an essential yet toxic trace element. The Ctr1 family of proteins plays a critical role for copper uptake in eukaryotes. However, the mechanisms of action of Ctr1 are largely unknown. Our previous data demonstrated that copper transport induces conformational changes in the cytosolic C terminus of the yeast Saccharomyces cerevisiae Ctr1. To define the physiological significance of this molecular event and gain better insights into the mechanism of Ctr1-mediated copper uptake, we have characterized the functional roles of the Ctr1 C terminus. A Ctr1 mutant lacking the entire C-terminal cytosolic tail is functional in high affinity copper uptake; however, yeast cells expressing this mutant are extremely sensitive to excess copper. Toxic copper uptake is not attributed to elevated expression or distinct subcellular localization of this mutant as compared with wild type Ctr1. Further characterization of the function of Ctr1 containing deletions or site-directed mutations at the C terminus indicates a structural role for the C terminus in controlling Ctr1 activities. In response to excess copper, Ctr1-mediated copper transport is rapidly blocked in a C terminus-dependent mechanism associated with direct binding of copper. We propose that conformational changes in the cytosolic tail of yeast Ctr1 by copper sensing within this domain lead to the inhibition of Ctr1-mediated copper transport. These data suggest a new regulatory mechanism by which yeast cells maintain homeostatic copper acquisition.

Original languageEnglish (US)
Pages (from-to)4112-4122
Number of pages11
JournalJournal of Biological Chemistry
Issue number7
StatePublished - Feb 13 2009

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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