Signaling from the BCR and CXCR5 activates WNK1 via PI3K and AKT. (A–J) Top: Immunoblots of cell lysates from mouse B cells stimulated for the indicated times with anti-IgM (A–D and I) or CXCL13 (E–H and J) using WT (A and E), WNK1-deficient or control B cells (B and F), B cells expressing kinase-inactive WNK1-D368A or control B cells (C and G), or WT B cells treated with vehicle (DMSO), an inhibitor of WNK family kinases (WNK463; D and H), a PI3K inhibitor (PI-103) or an AKT inhibitor (MK2206; I and J), probed with antibodies to phosphorylated OXSR1 (p-OXSR1), α-TUBULIN, phosphorylated AKT (p-AKT), phosphorylated PRAS40 (p-PRAS40) or ERK2. Bottom: Mean ± SEM abundance of p-OXSR1, p-AKT, and p-PRAS40 in the lanes above, normalized to α-TUBULIN or ERK2. Mann–Whitney test (A and E), two-way ANOVA (B–D, F–H, I, and J); *, 0.01 < P < 0.05; **, 0.001 < P < 0.01; ***, 0.0001 < P < 0.001; ****, P < 0.0001. Sample sizes: four (B, E, and J); five (C, F, G, and I); seven (D and H); and eight (A). Data are pooled from two (B, C, E, F, G, I, and J) or three (A, D, and H) independent experiments. Source data are available for this figure: SourceData F1.