Fig. 3: Overexpression of protein kinases decreases NBCe1-A activity.
From: Inactivation mechanisms of Na+/\({{\mathrm{HCO}}}_{3}^{-}\) cotransporter NBCe1 by phosphorylation
a Expression of endogenous protein phosphatase PP1 in Xenopus oocytes. Upper panel: oocytes of stages I − VI. Middle panel: Western blotting for PP1. Bottom a parallel gel stained with Coomassie brilliant blue to show the loading. See Fig. S4b for full blots. b Administration of PP1 inhibitor Calyculin inhibits NBCe1-A activity in oocytes. c, d Overexpressing SPAK and/or CaMKIIα has no effect on the activities of P-loop12A or P-lop12D. SPAKCA: constitutively-active SPAK containing mimic-phosphorylation mutations T243E and S383D. e SPAK significantly decreases the activity of NBCe1-A with mimic-phosphorylation at T254 and S256. f SPAK has no effect on NBCe1-A with mimic-(de)phosphorylation at S232, S233, and S235. The numerals in the parentheses on the bars indicate the number of individual oocytes. One-way ANOVA followed by post-hoc Dunnett’s multiple comparisons was used for statistical analyses for a, b. Student’s t-test was used for c, d, f. **p < 0.01; ***p < 0.001; ****p < 0.0001.
