Physiological relevance of regulation of the WNK/SPAK pathway by the IRBIT/PP1 pathway.
(A) Sealed pancreatic ducts were treated with 10 nM scrambled siRNA (black, red, and green traces), 5 nM IRBIT siRNA (red and blue traces), 2.5 nM IRBIT siRNA (green and purple traces), and 10 nM SPAK siRNA (blue and purple traces) and were used to measure stimulated ductal fluid secretion. (B) Sealed pancreatic ducts were treated with 10 nM scrambled (black trace) or SPAK siRNA (red trace). Ten minutes before and during the experiments, the ducts were treated with the indicated concentration of tautomycin, and fluid secretion was measured by video microscopy for 40 minutes. Results in A and B are mean ± SEM of 3–6 experiments.