Sodium-dependent phosphate transport protein 2A (NaPi-2a)

Sodium-dependent phosphate transport protein 2A (NaPi-2a) is a membrane transporter primarily localized to the renal proximal tubule brush border membrane, where it facilitates the active reabsorption of phosphate from the filtrate via sodium-coupled cotransport, accounting for approximately 70–80% of phosphate reabsorption in the kidney[3][6][1]. This protein, encoded by the SLC34A1 gene, is regulated by parathyroid hormone and plays a crucial role in maintaining systemic phosphate homeostasis. Mutations in SLC34A1 can lead to disorders such as hypophosphatemia with kidney stones and/or osteoporosis[3][6]. The cotransporter typically operates with a stoichiometry of 3 sodium ions per one divalent phosphate ion, making the process electrogenic[3].

Other names

Na(+)-dependent phosphate cotransporter 2ANa(+)/Pi cotransporter 2ANaPi-2aNaPi-3NPT2SLC34A1Sodium-phosphate transport protein 2ASodium/phosphate cotransporter 2ASolute carrier family 34 member 1

Substrate (transporter for phosphate and sodium ions); Electrogenic sodium-phosphate cotransport