Genetic separation of FK506 susceptibility and drug transport in the yeast Pdr5 ATP-binding cassette multidrug resistance transporter
Abstract
Overexpression of the yeast Pdr5 ATP-binding cassette transporter leads to pleiotropic drug resistance to a variety of structurally unrelated cytotoxic compounds. To identify Pdr5 residues involved in substrate recognition and/or drug transport, we used a combination of random in vitro mutagenesis and phenotypic screening to isolate novel mutant Pdr5 transporters with altered substrate specificity. A plasmid library containing randomly mutagenized PDR5 genes was transformed into appropriate drug-sensitive yeast cells followed by phenotypic selection of Pdr5 mutants. Selected mutant Pdr5 transporters were analyzed with respect to their expression levels, subcellular localization, drug resistance profiles to cycloheximide, rhodamines, antifungal azoles, steroids, and sensitivity to the inhibitor FK506. DNA sequencing of six PDR5 mutant genes identified amino acids important for substrate recognition, drug transport, and specific inhibition of the Pdr5 transporter. Mutations were found in each nucleotide-binding domain, the transmembrane domain 10, and, most surprisingly, even in predicted extracellular hydrophilic loops. At least some point mutations identified appear to influence folding of Pdr5, suggesting that the folded struc...Continue Reading
References
The a-factor transporter (STE6 gene product) and cell polarity in the yeast Saccharomyces cerevisiae
Citations
Improper protein trafficking contributes to artemisinin sensitivity in cells lacking the KDAC Rpd3p.
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Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections.
Allergy & Infectious Diseases (ASM)
Allergies result from the hyperreactivity of the immune system to some environmental substance and can be life-threatening. Infectious diseases are caused by organisms including bacteria, viruses, fungi and parasites. They can be transmitted different ways, such as person-to-person. Here is the latest research on allergy and infectious diseases.
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An antifungal, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis, cryptococcal meningitis, and others. Discover the latest research on antifungals here.