Rat RalBP1 is an ATP-dependent transporter of organic anions

Detoxification proceeds via covalent modifications (e.g. oxidation and/or c onjugation) of the offending compound followed by a transport step. A numbe r of relevant transporters, mostly belonging to the ABC superfamily, has be en identified. We have previously isolated and characterized a rat-liver AT P-dependent transporter of organic anions which, by its biochemical charact eristics, did not belong to the ABC superfamily. We now report that this tr ansporter is similar or identified to the Ral-binding protein RalBPl. We pr esent data demonstrating that RalBPl, expressed in Escherichia coli and par tially purified, has substrate-stimulated ATPase activity and, upon reconst itution, catalyzed ATP-dependent transport of organic anions. (C) 2001 Else vier Science Ireland Ltd. All rights reserved.