WNK1 and Hypertension: Based on the phenotype of familial hyperkalemia and hypertension (FHHt) (Wilson et al., 2001), and a report that WNK1 could stimulate SGK1 and ENaC (Xu et al., 2005a), we next generated and characterized WNK1−/− mpkCCD cells, also using the CRISPR/Cas9 system (Fig. 2A).