ABCMdb

PMID: 15517563

Garcia-Escarp M, Martinez-Munoz V, Sales-Pardo I, Barquinero J, Domingo JC, Marin P, Petriz J
Flow cytometry-based approach to ABCG2 function suggests that the transporter differentially handles the influx and efflux of drugs.
Cytometry A. 2004 Dec;62(2):129-38., [PubMed]

Sentences

No. Mutations Sentence Comment

0 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Flow Cytometry-Based Approach to ABCG2 Function Suggests That the Transporter Differentially Handles the Influx and Efflux of Drugs Marta Garcı´a-Escarp,1 Vanessa Martı´nez-Mun˜oz,3 Irene Sales-Pardo,3 Jordi Barquinero,1 Joan Carles Domingo,2 Pedro Marin,3 and Jordi Petriz3 * 1 Unitat de Diagno`stic i Tera`pia Molecular, Centre de Transfusio´ i Banc de Teixits, Barcelona, Spain 2 Departament de Bioquı´mica i Biologia Molecular, Universitat de Barcelona, Barcelona, Spain 3 Area de Criopreservacio´, Centre de Diagno`stic Biome`dic, Hospital Clı´nic, Institut d`Investigacions Biome`diques August Pi i Sunyer, Universitat de Barcelona, Barcelona, Spain Received 3 February 2004; Revision Received 25 February 2004; Accepted 23 April 2004 Background: To better characterize the function of the ABCG2 transporter in vitro, we generated three cell lines (MXRA, MXRG, and MXRT) stably expressing ABCG2 after transfection of wild-type ABCG2 and two mutants (R482G and R482T), respectively. Login to comment 117 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly ABCG2 p.Arg482Ala KB cells transfected with ABCG2-R482A, R482G, and R482T were seeded in the presence of 0.8 ␮M MXR for 1 h at 37°C. Login to comment 154 ABCG2 p.Arg482Ala Using ABCG2 variant-transfected KB cells, we clearly demonstrated that MXR retention is significantly lower than that observed with wt R482A (MXRA) cells. Login to comment 156 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Moreover, MXR is pumped out of the cells more efficiently by R482T and R482G mutants than by wt ABCG2. Login to comment 174 ABCG2 p.Arg482Gly In this study, we found that the mutation R482G, which changes the amino acid arginine to a glycine, results in a faster efflux of MXR when compared with MXRT cells, suggesting that the enhanced ability to transport MXR increases resistance to this drug. Login to comment 178 ABCG2 p.Arg482Gly Functional assay for transport kinetics in R482G transfected cell lines. Efflux assays were performed with 0.8 ␮M MXR, 100 ng/ml Rho123, and 50 nM SYTO-13 in the selected cell line. Login to comment 182 ABCG2 p.Arg482Gly This supports the hypothesis that the R482G mutation is crucial for enhanced MXR resistance, because it allows an increased efflux of the drug, but it may also significantly decrease the intracellular levels of MXR. Login to comment 183 ABCG2 p.Arg482Thr In contrast, the R482T mutation may play a critical role in this decreased MXR retention, rather than in the increased velocity of the transporter. Login to comment 200 ABCG2 p.Arg482Gly The R482G mutation seems to be essential to increase the velocity of this ABCG2 form and to decrease the intracellular accumulation of MXR. Login to comment