Figure 2.

High-K⁺ gavage dephosphorylates NaCl cotransporter (NCC) and not STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) in kidney slices. C57/BL6 mice were gavaged with either control (2% sucrose) or 3% K⁺ (2% sucrose + 3% KCl) for 15 min. A: protein extracts from whole kidney homogenates were immunoblotted for phosphorylated (p)NCC at Thr⁵³ (pNCC-T53), NCC, and β-actin. B: dot plot depicting the densitometric ratios of pNCC-T53 and NCC. C: blot of pSPAK at Ser³⁸³ (pSPAK-S383), full-length SPAK (FL-SPAK), and β-actin. D: dot plot depicting the densitometric ratios of pSPAK-S383 and FL-SPAK. Each solid black circle represents the immunoblot densitometric ratio from individual control gavaged mouse, whereas each solid black square represents the immunoblot densitometric ratio from individual 3% K⁺ gavaged mouse (means ± SD, n = 5 per group). Comparisons were performed with a Mann–Whitney test. P values are indicated. NS indicates P > 0.05 (not significant). pOxSR1-S335, phosphorylated oxidative stress responsive kinase 1 at Ser³³⁵.