ABCC1(ATP-BINDING CASSETTE, SUBFAMILY C, MEMBER 1),also called MRP1 or MRP, is a protein that in humans is encoded by the ABCC1 gene. The ABCC1 is a member of the superfamily of ATP-binding cassette (ABC) transporters. The ABCC1 is a plasma membrane drug-efflux pump.The ABCC1 gene is mapped to chromosome 16p13.1 by isotopic in situ hybridization. ABCC1 functions as a multispecific organic anion transporter, with oxidized glutathione, cysteinyl leukotrienes, and activated aflatoxin B1 as substrates and it also transports glucuronides and sulfate conjugates of steroid hormones and bile salts. Blocking ABCC1 efflux pumps increases the susceptibility of the cells to the toxic effects of unconjugated bilirubin, suggesting that ABCC1 is an important protector in this scenario. ABCC1 clears beta-amyloid from brains of mice and can be activated by thiethylperazine.And Chemotaxis assays show that ABCC1-mediated transport of S1P influenced mast-cell migration, but not mast-cell degranulation.