STK39 and Hypertension: To date, several compounds/drugs have been designed for the treatment of diseases caused by the activation of WNK-OSR1/SPAK signaling such as hypertension, and they are WNK inhibitors, OSR1/SPAK inhibitors and WNK-SPAK/OSR1 binding disruptors (Table 2) [66, 89, 92, 94, 100, 120–130].