Use of a Yeast-Based Membrane Protein Expression Technology to Overexpress Drug Resistance Efflux Pumps

Azole antifungal drugs are used widely to treat people with oral fungal infections. Unfortunately, fungi can develop resistance to these drugs. This resistance can be due to the overexpression or mutation of cytochrome P450 14α-lanosterol demethylase, also known as ERG11 or CYP51 , and/or the overexpression of membrane-located multidrug efflux pumps. We have developed a heterologous membrane protein expression system that can be used to study the structure and function of these proteins in the non-pathogenic, genetically stable, and versatile eukaryotic model organism, Saccharomyces cerevisiae . In this chapter we describe the techniques used to express the Candida albicans efflux pump Cdr1p in S. cerevisiae .