Exchange of Cytosolic Bicarbonate for Extracellular Chloride by Band 3 Anion Exchanger (AE1, SLC4A1) Authored: May, B, 2011-03-24 Edited: May, B, 2011-03-24 Pubmed11606574 Pubmed12933803 Pubmed8972395 Reactome Database ID Release 431237038 Reactome, http://www.reactome.org ReactomeREACT_121292 Reviewed: Jassal, B, 2012-04-27 The band 3 anion exchange protein (AE1, SLC4A1) exchanges chloride (Cl-) for bicarbonate (HCO3-) across the plasma membrane according to the concentration gradients of the anions (Knauf et al. 1996, Dahl et al. 2003). SLC4A1 may be part of a complex ("metabolon") with carbonic anhydrase II (CA2) which would facilitate the transport of HCO3- (Sterling et al. 2001).