The function of ENSG00000125257 (ABCC4, ATP binding cassette subfamily C member 4 (PEL blood group)) is as follows. ATP-dependent transporter of the ATP-binding cassette (ABC) family that actively extrudes physiological compounds and xenobiotics from cells (PubMed:11856762, PubMed:12523936, PubMed:15364914, PubMed:38886124, PubMed:40138312). Transports a range of endogenous molecules that have a key role in cellular communication and signaling, including cyclic nucleotides such as cyclic AMP (cAMP) and cyclic GMP (cGMP), bile acids, steroid conjugates, urate, and prostaglandins (PubMed:11856762, PubMed:12523936, PubMed:12835412, PubMed:12883481, PubMed:15364914, PubMed:15454390, PubMed:16282361, PubMed:17959747, PubMed:18300232, PubMed:26721430, PubMed:38886124, PubMed:40138312). Mediates the ATP-dependent efflux of glutathione conjugates such as leukotriene C4 (LTC4) and leukotriene B4 (LTB4) too. The presence of GSH is necessary for the ATP-dependent transport of LTB4, whereas GSH is not required for the transport of LTC4 (PubMed:17959747). Mediates the cotransport of bile acids with reduced glutathione (GSH) (PubMed:12523936, PubMed:12883481, PubMed:16282361). Transports a wide range of drugs and their metabolites, including anticancer, antiviral and antibiotic molecules (PubMed:11856762, PubMed:12105214, PubMed:15454390, PubMed:17344354, PubMed:18300232). Confers resistance to anticancer agents such as methotrexate (PubMed:11106685). {ECO:0000269|PubMed:11106685, ECO:0000269|PubMed:11856762, ECO:0000269|PubMed:12105214, ECO:0000269|PubMed:12523936, ECO:0000269|PubMed:12835412, ECO:0000269|PubMed:12883481, ECO:0000269|PubMed:15364914, ECO:0000269|PubMed:15454390, ECO:0000269|PubMed:16282361, ECO:0000269|PubMed:17344354, ECO:0000269|PubMed:17959747, ECO:0000269|PubMed:18300232, ECO:0000269|PubMed:26721430, ECO:0000269|PubMed:38886124, ECO:0000269|PubMed:40138312}.