This entry represents the multidrug resistance-associated protein 5 (MRP5 or ABCC5). It belongs to the MRP (multidrug resistance protein) subfamily of the ATP-binding cassette (ABC) transporter family []. It is a cyclic nucleotide organic anion transporter, mediating the efflux of a variety of organic anions, including certain monophosphate nucleotide metabolites such as cGMP and cAMP, and certain purine analogues [, ]. MRP5 acts as a selective transporter of cGMP in pituitary cells [].MRP5 is elevated in lung, colon, pancreatic and breast cancer samples and also in the heart following ischemic episodes []. MRP5 could confer resistance to several anticancer drugs, including cisplatin, purine analogues (such as 6-mercaptopurine and 6-thioguanine), pyrimidine analogues (such as gemcitabine, cytosine arabinoside (Ara-C) and 5-fluorouracil (5-FU)) , the natural product doxorubicin and to anti-folate drugs (such as MTX), but not to Vinca alkaloids (such as vincristine) [].
