Sodium-chloride symporter (NCC) (NCC)

The Sodium-chloride symporter (NCC), also known as the thiazide-sensitive Na-Cl cotransporter, is a transmembrane protein encoded by the SLC12A3 gene and is primarily located in the apical membrane of the distal convoluted tubule (DCT) of the kidney [1, 2]. It plays a vital role in renal electrolyte homeostasis by mediating the electroneutral reabsorption of sodium and chloride ions from the tubular fluid, which accounts for approximately 5% to 10% of the total filtered sodium load [1, 10]. This reabsorption process is a key regulator of extracellular fluid volume and long-term arterial blood pressure [8, 14]. Mutations leading to a loss of NCC function result in Gitelman syndrome, a salt-wasting disorder characterized by hypotension, hypokalemia, and metabolic alkalosis [2, 4]. In contrast, overactivity of the symporter, often caused by mutations in regulatory kinases like WNK1 or WNK4, leads to Pseudohypoaldosteronism type II (Gordon's syndrome), which is marked by hypertension and hyperkalemia [1, 10]. NCC is the pharmacological target for thiazide and thiazide-like diuretics, such as hydrochlorothiazide and chlorthalidone, which are first-line therapies for essential hypertension and edema [8, 12]. These drugs inhibit the symporter by competing with chloride ions for the binding site, thereby increasing the urinary excretion of sodium and water to lower blood pressure [7, 13].

Other names

SLC12A3NCCNCCTTSCThiazide-sensitive Na-Cl cotransporterSolute carrier family 12 member 3Na-Cl symporter

Inhibition of the sodium-chloride symporter by competing for the chloride-binding site, which prevents the reabsorption of sodium and chloride ions in the distal convoluted tubule, leading to increased urinary excretion of salt and water.