Figure 4.

Immunogold labeling of type II cells. (A) Labeling for caldesmon (CALD) is sparse and both cytoplasmic (arrows) and nuclear (arrowheads). (B) Labeling for AQP1 is also sparse but present on the plasma membrane of the fine processes (arrows) and occasionally in the cytoplasm (arrowhead). (C) Labeling for S-100 is strong in the cytoplasm and stronger in the nucleus (n), while mitochondria (arrows) and chromatin have relatively few gold particles over them. Labeling is also present in the fine processes. (D) Labeling for α1Na,K-ATPase is moderate and specific mostly to the plasma membrane, especially the fine processes, and less commonly in the cytoplasm. Scale bars: A–C = 2 µm; D = 1 µm.