Table 1.
Main channels, transporters, and other proteins relevant in salt absorption along the TAL
| Genetic locus | Protein name | Cellular localization | Main biological functions | Correlated genetic human disease |
|---|---|---|---|---|
| SLC12A1 | NKCC2 | Apical site | Na+, Cl–, K+ transport; ammonia transport | BS type I |
| KCNJ1 | ROMK | Apical site | K+ recycling to the lumen | BS type II |
| CLCNKB | ClC-Kb | Basolateral site | Cl– exit from the cells to the interstitium | BS type III |
| BSND | Barttin | Basolateral site | Cl– exit from the cells to the interstitium | BS type IV |
| CASR | CaSR | Basolateral site | Regulation of transcellular and paracellular salt absorption | BS type V |
| UMOD | Uromodulin (Tamm–Horsfall protein) | Apical site | Regulation of NKCC2 phosphorylation; regulation of ROMK surface expression | UAKD |
Abbreviations: UAKD, uromodulin-associated kidney disease; TAL, thick ascending limb of the loop of Henle; ROMK, renal outer medulla K+ channels; CaSR, calcium sensing receptor; NKCC2, Na-K-2Cl cotransporter; BS, Bartter syndrome.