The Human Multidrug Resistance-Associated Protein Functionally Complements the Yeast Cadmium Resistance Factor 1

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 93; no. 13; pp. 6743 - 6748
• Main Authors: Tommasini, Roberto, Evers, Raymond, Vogt, Esther, Mornet, Clotilde, Guido J. R. Zaman, Schinkel, Alfred H., Borst, Piet, Martinoia, Enrico
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 25-06-1996; National Acad Sciences; National Academy of Sciences
• Subjects: ATP Binding Cassette Transporter, Subfamily B, Member 1 - genetics; ATP Binding Cassette Transporter, Subfamily B, Member 1 - metabolism; ATP-Binding Cassette Transporters; Base Sequence; Cadmium; Cell membranes; Cellular biology; Cloning, Molecular; Complementary DNA; DNA Primers; Drug Resistance, Multiple; Epithelial cells; Fractionation; Fungal Proteins - genetics; Genes; Genetic Complementation Test; Glutathione - analogs & derivatives; Glutathione - metabolism; Humans; Microsomes; Microsomes - metabolism; Molecular Sequence Data; Proteins; Pumps; R factors; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; Subcellular Fractions - metabolism; Vacuoles; Vacuoles - metabolism; Yeast; Yeasts
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.93.13.6743

A Saccharomyces cerevisiae strain with a disrupted yeast cadmium resistance factor (YCF1) gene (DTY168) is hypersensitive to cadmium. YCF1 resembles the human multidrug resistance-associated protein MRP (63% amino acid similarity), which confers resistance to various cytotoxic drugs by lowering the intracellular drug concentration. Whereas the mechanism of action of YCF1 is not known, MRP was recently found to transport glutathione S-conjugates across membranes. Here we show that expression of the human MRP cDNA in yeast mutant DTY168 cells restores cadmium resistance to the wild-type level. Transport of S-(2,4-dinitrobenzene)-glutathione into isolated yeast microsomal vesicles is strongly reduced in the DTY168 mutant and this transport is restored to wild-type level in mutant cells expressing MRP cDNA. We find in cell fractionation experiments that YCF1 is mainly localized in the vacuolar membrane in yeast, whereas MRP is associated both with the vacuolar membrane and with other internal membranes in the transformed yeast cells. Our results indicate that yeast YCF1 is a glutathione S-conjugate pump, like MRP, and they raise the possibility that the cadmium resistance in yeast involves cotransport of cadmium with glutathione derivatives.