Cell Biology of H+ Transport in Epithelia

RESUMO

Cell homeostasis of H+ ions has been an object of wide interest in the last two decades, which has led to extended knowledge about a considerable number of membrane transport mechanisms responsible for keeping cell pH within physiological limits. Among these mechanisms the most important are Na+/H+ exchange, the vacuolar H+-ATPase, the H+-K+-ATPase, Cl-/HCO3 - exchange and Na+/HCO3 - cotransport. The present review covers both cellular function and molecular aspects of these transporters, starting from a discussion of the methods used for the determination of cell pH and epithelial H+ transport, and analysing their molecular constitution, cloning and known isoforms, as well as their functional role in the maintenance of cell pH and epithelial transport.