Figure 1. Relative abundance of NHE1 and AE2 at various regions in the mucosa of the human conducting airways. Relative abundance of NHE1 (top) and AE2 (bottom) was determined by calculating the ratio of their density to the density of GAPDH (the internal standard glyceraldehyde-3-phosphate dehydrogenase). Values represent the mean+SEM of 3-5 independent samples from 3-5 organ donors normalized to GAPDH.