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. Author manuscript; available in PMC: 2010 Nov 1.
Published in final edited form as: J Voice. 2008 Dec 25;23(6):658–665. doi: 10.1016/j.jvoice.2008.03.010

Figure 1. Model of transport proteins underlying transcellular ion and water fluxes.

Figure 1

Legend: The sodium-potassium pump (Na+K+ATPase) was immunolocalized to the basolateral (serosal) plasma membrane where it establishes an electrochemical gradient creating a driving force for transcellular ion movement. The sodium-potassium-chloride (Na+K+2Cl−) cotransporter provides a pathway for Na+, K+ and Cl− entry into the cells. The Na+ also enter the cells via epithelial sodium channels (ENaC) located on the luminal (air-facing) surface. The Cl− exit cells via cystic fibrosis transmembrane regulator (CFTR) chloride channels and calcium-activated chloride channels (CaCC) also located on the luminal surface. Luminal aquaporins provide a pathway for bidirectional water fluxes across the cell membrane.