Chimeras of Candida albicans Cdr1p and Cdr2p reveal features of pleiotropic drug resistance transporter structure and function

Mol Microbiol. 2011 Oct;82(2):416-33. doi: 10.1111/j.1365-2958.2011.07820.x. Epub 2011 Sep 19.


Members of the pleiotropic drug resistance (PDR) family of ATP binding cassette (ABC) transporters consist of two homologous halves, each containing a nucleotide binding domain (NBD) and a transmembrane domain (TMD). The PDR transporters efflux a variety of hydrophobic xenobiotics and despite the frequent association of their overexpression with the multidrug resistance of fungal pathogens, the transport mechanism of these transporters is poorly understood. Twenty-eight chimeric constructs between Candida albicans Cdr1p (CaCdr1p) and Cdr2p (CaCdr2p), two closely related but functionally distinguishable PDR transporters, were expressed in Saccharomyces cerevisiae. All chimeras expressed equally well, localized properly at the plasma membrane, retained their transport ability, but their substrate and inhibitor specificities differed significantly between individual constructs. A detailed characterization of these proteins revealed structural features that contribute to their substrate specificities and their transport mechanism. It appears that most transmembrane spans of CaCdr1p and CaCdr2p provide or affect multiple, probably overlapping, substrate and inhibitor binding site(s) similar to mammalian ABC transporters. The NBDs, in particular NBD1 and/or the ∼150 amino acids N-terminal to NBD1, can also modulate the substrate specificities of CaCdr1p and CaCdr2p.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry*
  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism*
  • Antifungal Agents / metabolism
  • Antifungal Agents / pharmacology
  • Biological Transport
  • Candida albicans / chemistry
  • Candida albicans / drug effects
  • Candida albicans / genetics
  • Candida albicans / metabolism*
  • Drug Resistance, Fungal
  • Fungal Proteins / chemistry*
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Protein Structure, Tertiary
  • Protein Transport
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism


  • ATP-Binding Cassette Transporters
  • Antifungal Agents
  • Fungal Proteins
  • Recombinant Fusion Proteins