Fig. 4.

Distribution of V₀ and V₁ components in control and forskolin-treated (100 μM) salivary glands. Cross sections through salivary glands were double-labeled with antibodies against V₀ subunit d (red in A, B, E, and F) and actin (green in E and F) or antibodies against V₁ subunit B (red in C, D, G, and H) and V₀ subunit d (green in G and H). (E and F). The apical membrane with its deep infoldings (= canaliculi; arrows) is revealed by intense labeling for actin. Asterisks indicate the lumen of the gland. (A and B) Subunit d is highly enriched on the apical membrane in control and forskolin-treated glands. (C, D, G, and H) Subunit B is concentrated at the apical membrane only in the forskolin-treated gland. Vesicular staining for subunit d (arrowheads) is frequent in the control (A) and reduced in forskolin-treated cells (B). These structures are stained for subunit d but not subunit B (D and H Insets). (Scale bar, 20 μm.)