Figure 4.

Comparison of γENaC species in total microsomes and surface fractions of rat kidney. Rats were fed a low-Na diet for 1 wk. Microsomes and neutravidin eluates were obtained from two different biotinylated rat kidneys, before and after treatment with PNGaseF. Microsome lanes were loaded with 30 µg of protein. Eluate lanes were loaded with material corresponding to 600 µg of starting material. Before treatment, whole microsomes had a full-length band migrating at 80 kDa and a broader cleaved band migrating at ∼65 kDa. The 65 kDa band predominated in the eluates. After treatment with PNGaseF, three species were apparent in whole microsome fractions migrating at 65 kDa, 55 kDa, and a doublet at 50 kDa. In the eluate, the 50 kDa doublet predominated. Results are typical of three blots, although the doublet was not always resolved. ENaC, epithelial Na channel.