Anion exchanger AE1 as a candidate pathway for taurine transport in rat erythrocytes
Conejero, C.
American Journal of Physiology 272(5 Pt 1): C1457-C1464
1997
ISSN/ISBN: 0002-9513 PMID: 9176135 Document Number: 482885
Taurine has been shown to act as an osmolyte during the regulatory volume decrease process in a variety of cell types. The nature of the taurine efflux carrier is thought to consist of a diffusional pathway with pharmacological properties similar to a chloride channel or through an anion exchanger. We propose that taurine is a substrate of the anion exchanger AE1, also called band 3. Experiments were performed in rat erythrocytes, which express large amounts of band 3. Taurine uptake and efflux transport experiments were determined in the presence of inhibitors of anion carriers and chloride channels. and efflux transport experiments were determined in the Both taurine uptake and efflux were inhibited by band 3 inhibitors 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS), niflumic acid, or furosemide. Moreover, DIDS competes with taurine at a common binding site in the uptake process. Specific inhibitors of the electroneutral cotransport as well as inhibitors of the chloride channels were ineffective in blocking taurine transport. Thus we suggest that band 3 may be the protein responsible for taurine transport in rat erythrocytes.