Multidrug resistance is a major challenge in the therapy of cancer and pathogenic fungal infections. More than three decades ago, P-glycoprotein was the first identified multidrug transporter. It has been studied exten-sively at the genetic and biochemical levels ever since. Pdr5, the most abun-dant ATP-binding cassette transporter in Saccharomyces cerevisiae,is highly homologous to azole-resistance-mediating multidrug transporters in fungal pathogens, and a focus of clinical drug resistance research. .
