ABCG2 is a translocation protein used to actively pump drugs and other compounds against their concentration gradient using the bonding and hydrolysis of ATP as the energy source.

[1] The membrane-associated protein encoded by this gene is included in the superfamily of ATP-binding cassette (ABC) transporters.

[8] Additionally, many ABC transporters have conserved NBD regions showing the strict conformation needed to bind ATP molecules.

[8] Early observations of significant ABCG2-mediated resistance to anthracyclines were subsequently attributed mutations encountered in vitro but not in nature or the clinic.

Significant expression of this protein has been observed in the placenta,[9] and it has been shown to have a role in protecting the fetus from xenobiotics in the maternal circulation.