ATP-dependent transporter of the ATP-binding cassette (ABC) family that actively extrudes physiological compounds, and xenobiotics from cells. Participates in physiological processes involving bile acids, conjugated steroids and cyclic nucleotides. Stimulates the ATP-dependent uptake of a range of physiological lipophilic anions, including the glutathione S-conjugates leukotriene C4 and dinitrophenyl S-glutathione, steroid sulfates such as dehydroepiandrosterone 3-sulfate (DHEAS) and estrone 3-sulfate, glucuronides such as estradiol 17-beta-D-glucuronide (E(2)17betaG), the monoanionic bile acids glycocholate and taurocholate, and methotrexate. Enhances also the cellular extrusion of cAMP and cGMP. Confers resistance to anticancer drugs, such as 5-fluorouracil (5-FU) and methotrexate. Probably functions to secrete earwax. Required for the secretion of components contributing to axillary odor formation.