Fig. 9
From: Bicarbonate transport of airway surface epithelia in luminally perfused mice bronchioles
A hypothetical model for H+/HCO3− transport across the apical membrane of airway surface epithelial cells in mice bronchiole. HCO3− secretion across the apical membrane is largely mediated by CFTR and Slc26a9 Cl−–HCO3− exchanger. CaCC is also involved in HCO3− secretion. An unknown HCO3−-permeable anion channel or HCO3− transporter is upregulated in CF bronchioles. ENaC is involved in the regulation of HCO3− transport but the mechanisms are not clear. NHE2 and NBC contribute to the regulation of intracellular and ASL pH