RTA2 is involved in calcineurin-mediated azole resistance and sphingoid long-chain base release in Candida albicans

Cell Mol Life Sci. 2009 Jan;66(1):122-34. doi: 10.1007/s00018-008-8409-3.

Abstract

The calcineurin pathway has been reported to be essential for the development of azole resistance in Candida albicans. The depletion or ectopic over-expression of RTA2 increased or decreased susceptibility of C. albicans to azoles, respectively. CaCl(2)- induced activation of the calcineurin pathway in wildtype C. albicans promoted resistance to azoles, while the Ca(2+) chelator (EGTA), calcineurin inhibitors (FK506 and cyclosporin A) and the deletion of RTA2 blocked the resistance-promoting effects of CaCl(2). Furthermore, we found that RTA2 was up-regulated in a calcineurin-dependent manner. The depletion of RTA2 also made the cell membrane of C. albicans liable to be destroyed by azoles and RTA2 over-expression attenuated the destroying effects. Finally, the disruption of RTA2 caused an increased accumulation of dihydrosphingosine (DHS), one of the two sphingolipid long-chain bases, by decreasing release of DHS. In conclusion, our findings suggest that RTA2 is involved in calcineurin-mediated azole resistance and sphingoid long-chain base release in C. albicans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifungal Agents / pharmacology*
  • Azoles / pharmacology*
  • Biological Transport / drug effects
  • Calcium / pharmacology
  • Candida albicans / drug effects*
  • Candida albicans / genetics
  • Candida albicans / metabolism
  • Candida albicans / ultrastructure
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Drug Resistance, Fungal / genetics
  • Drug Resistance, Fungal / physiology*
  • Ergosterol / biosynthesis
  • Fungal Proteins / chemistry
  • Fungal Proteins / genetics
  • Fungal Proteins / physiology*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Microbial Sensitivity Tests
  • Rhodamines / metabolism
  • Sphingosine / analogs & derivatives
  • Sphingosine / metabolism
  • Up-Regulation

Substances

  • Antifungal Agents
  • Azoles
  • Fungal Proteins
  • Membrane Proteins
  • Rhodamines
  • rhodamine 6G
  • Sphingosine
  • safingol
  • Calcium
  • Ergosterol