Transport of glutathione-conjugates in human erythrocytes

The last step of detoxification of both endogenous and environmental toxicants is typically a conjugation that produces a bulky hydrophilic molecule. The excretion of such conjugates out of cells is of sufficient biological importance to have led to the evolution of ATP-driven export pumps for this purpose. The substrate specificity of such transporters is broad, and in some cases it has been shown to include not only anionic conjugates but also neutral or weakly cationic drugs. In the present article, we review the molecular identity, functional and structural characteristics of these pumps, mainly on the example of human erythrocytes, and discuss their physiological role in detoxification and in the multidrug resistance phenotype of cancer cells.