text: Drugs or toxic chemicals are useful in killing pathogenic bacteria or tumor cells, and studying how they mechanistically develop tolerance to a wide range of drugs can improve anti-bacterial and cancer therapeutics. Pdr5p has a similar mechanism of actions and functions to human multidrug resistance protein, whose overexpression is shown to provide chemical tolerance to cancer cells. Studying Pdr5p and how it is regulated by Pdr1p in yeast can give insights into how multi drug resistance occurs in mammals.
  By using pdr1-3 and fusing the promoter of Pdr5p to genes that code for membrane proteins of interests, yeast membrane proteins such as Pdr5p, Yor1, and Drs2 can be expressed highly so that they can be efficiently cloned and purified for further studies.