NKCC2 encoded by the Slc12a1 gene shows at least six alternatively spliced variants and has the ability to form dimmers. NKCC2 activity and expression can be found in the medullary and cortical thick ascending limb of Henle's loop is the nephron and in macula densa cells.nNKCC2 allows Na+ and Cl− entry from the tubule lumen into the thick ascending limb of Henle's loop, a process that allows reabsorbing 25–30% of the NaCl filtered by the glomeruli.In addition, NKCC2 can sense luminal Cl− concentration and initiates the signal for tubuloglomerular feedback in the specialized cells of the macula densa. Thus, NKCC2 activity is essential for salt conservation and for acute and chronic regulation of water balance.
