ATP-binding cassette super-family G member 2 is a protein that in humans is encoded by the ABCG2gene.[6][7] ABCG2 has also been designated as CDw338 (cluster of differentiation w338). 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]
ABCG2 forms into a homodimer to assume its active transport conformation. The dimer weighs approximately 144 kDa. The expression of this transport protein is highly conserved throughout the animal kingdom, pointing to its importance.[8]
Substrate binding with compounds occurs in the large central cavity. ABCG2 can bind to a broad range of compounds but binds strongest to flat, polycyclic chemicals with lots of hydrophobic character.[1]