Figure 5.

Hypothetical model of MST3 function on 2% KCl diets. NKCC2 and NCC in TAL and DCT1, respectively, are inhibited upon an increase in K⁺ intake, thus, delivering Na⁺ and water to the DCT2/CNT. Na⁺ in the DCT2/CNT is reabsorbed through ENaC, resulting in K⁺ secretion due to an electrochemical gradient. Reabsorption of Na⁺ through ENaC at the DCT2/CNT prevents Na⁺ loss. An increase in K⁺ intake stimulates MST3 expression, which inhibits NKCC2 and ENaC expression at the apical membrane of the nephron, thus preventing excessive absorption of Na⁺ and maintaining Na⁺ homeostasis.