Fig. 4.

Effect of various L-WNK1 isoforms on the activity of the SLC12 family members under hypotonic conditions. Xenopus laevis oocytes were injected with 0.2 μg/μl of KCC1 (A), KCC3a (B), KCC4 (C), KCC2a (D), or NKCC1 (E) cRNA alone or together with 0.1 μg/μl of L-WNK1-Δ9 or L-WNK1-Δ9–11–12 cRNA, as stated. ⁸⁶Rb⁺ uptake was assessed 48 h later in hypotonic conditions (110 and 155 mosmol/kgH₂O, respectively for KCCs and NKCC1). The pooled data from 3 different experiments are shown as percentage of cotransporter activity with means ± SE; n = 3 (10–15 oocytes per group, per experiment were tested). *Significantly different from the uptake observed in control alone (P < 0.001, by Student's t-test).