Sodium-potassium-chloride cotransporter type 2 (NKCC2)

Sodium-potassium-chloride cotransporter type 2 (NKCC2) is a membrane transport protein encoded by the SLC12A1 gene. It is found almost exclusively in the thick ascending limb of Henle’s loop within the kidney. Its primary function is to mediate secondary active transport—moving one sodium ion, one potassium ion, and two chloride ions from urine back into blood plasma. This process plays a critical role in maintaining body salt balance, extracellular fluid volume, and systemic blood pressure. The activity of NKCC2 underlies much of normal renal salt handling as well as pathophysiological states such as hypertension or edema when dysregulated. Clinically important drugs known as loop diuretics—including furosemide, bumetanide, and torsemide—exert their effects by inhibiting this transporter; these agents are mainstays for managing conditions characterized by excess fluid retention or high blood pressure.

Other names

NKCC2Sodium-(potassium)-chloride cotransporter 2Bumetanide-sensitive sodium-(potassium)-chloride cotransporter 2BSC1SLC12A1

Drugs targeting NKCC2 act as inhibitors. They block sodium-potassium-chloride reabsorption in the thick ascending limb of Henle’s loop in the kidney. This leads to increased excretion of sodium and water (diuresis), reducing blood volume and pressure—key for treating hypertension and edema.