Fig. 6.

Effect of A-kinase-anchoring protein-PKA and aquaporin 2 (AQP2)-synapse-associated protein-97 (SAP97) interactions on forskolin (FSK)- and arginine-vasopressin (AVP)-mediated phosphorylation of AQP2 on Ser²⁵⁶. A and B: LLC-PK₁ cells expressing wild-type (WT) c-Myc-AQP2 or c-Myc-AQP2∆PDZ were incubated with 50 µM indomethacin (Indo) overnight and then exposed to 80 nM AVP (I/AVP) or 20 µM FSK (I/FSK) for 10 min at 37°C. C: cells stably expressing WT c-Myc-AQP2 exposed to Indo overnight were incubated with 50 µM st-Ht31 or st-Ht31-pro for 30 min before exposure to AVP or FSK for 10 min. D and E: cells stably expressing scrambled (Scr) or pig SAP97 shRNA were transiently transfected with WT c-Myc-AQP2. These cells were incubated with Indo overnight and then exposed to AVP or FSK and processed as described in A and B. A′–E′: graphical representation of combined densitometry results of phospho-Ser²⁵⁶ AQP2/β-actin in means ± SD from n = 5 experiments. Open bars indicate Indo (control), lightly shaded bars indicate I/AVP, and dark shaded bars indicate I/FSK. Statistical comparisons in A′−E′ between Indo, I/AVP, and I/FSK were carried out by one-way ANOVA followed by a Bonferroni’s test. NS, nonsignificant differences. *P < 0.05; **P < 0.01; ***P < 0.001.