Broad substrate specificity ATP-binding cassette transporter ABCG2 (ABCG2)

High-capacity urate exporter working in both renal and extrarenal urate excretion. Plays a role in porphyrin homeostasis as it is able to mediates the export of protoporhyrin IX (PPIX) both from mitochondria to cytosol and from cytosol to extracellular space, and cellular export of hemin, and heme.

Xenobiotic transporter that may play an important role in the exclusion of xenobiotics from the brain. Appears to play a significant role in the multidrug resistance phenotype of many cancer cell lines.