<p>Proteins of the Ca2+:Cation Antiporter (CaCA) family are found ubiquitously, having been identified in animals, plants, yeast, archaea and widely divergent bacteria. All of the characterised animal proteins catalyze Ca2+:Na+ exchange although some also transport K+. The NCX1 plasma membrane protein exchanges 3 Na+ for 1 Ca2+. The <taxon tax_id="562">Escherichia coli</taxon> ChaA protein catalyses Ca2+:H+ antiport but may also catalyze Na+:H+ antiport. All remaining well-characterised members of the family catalyze Ca2+:H+ exchange.</p> <p>This family is specific for the calcium ion/proton exchangers of the CaCA family.</p> Calcium/proton exchanger