PT - JOURNAL ARTICLE AU - Christopher A. Larson AU - Preston L. Adams AU - Brian G. Blair AU - Roohangiz Safaei AU - Stephen Howell TI - The Role of the Methionines and Histidines in the Transmembrane Domain of Mammalian Copper Transporter 1 in the Cellular Accumulation of Cisplatin AID - 10.1124/mol.110.064766 DP - 2010 Jun 02 TA - Molecular Pharmacology PG - mol.110.064766 4099 - http://molpharm.aspetjournals.org/content/early/2010/06/02/mol.110.064766.short 4100 - http://molpharm.aspetjournals.org/content/early/2010/06/02/mol.110.064766.full AB - Mammalian Copper Transporter 1 (CTR1) is a high affinity Cu influx transporter that also mediates uptake of platinum-containing chemotherapeutic agents including cisplatin (cDDP). Methionines 150, 154 and histidine 139 have been proposed to form a series of stacked rings in the pore formed by the CTR1 homotrimer, each of which is required for maximal Cu transport. To examine the mechanism by which hCTR1 also transports cDDP, variant forms of hCTR1 in which methionines 150 and 154 were converted to isoleucines, or in which histidine 139 was converted to alanine, were re-expressed in cells in which both alleles of CTR1 had been knocked out. Each of these conversions disabled Cu transport and increased cellular resistance to the cytotoxic effect of Cu. In contrast, conversion of the methionines increased the uptake and cytotoxicity of cDDP well above that attained with wild type hCTR1. Conversion of H139 to alanine did not impair cDDP uptake and actually enhanced cytotoxicity. Thus, while M150 and 154 facilitate the movement of Cu through the pore, they serve to obstruct the passage of cDDP. None of the modifications altered the ability of cDDP to trigger the degradation of hCTR1 indicating that cDDP must interact with hCTR1 at other sites as well. While both Cu and cDDP may rely on a series of transchelation reactions to pass through the hCTR1 trimeric complex, the details of the molecular interactions must be different which provides a potential basis for selective pharmacologic modulation of Cu versus cDDP cytotoxicity.The American Society for Pharmacology and Experimental Therapeutics