Sodium-dependent phosphate transporter type III (PiT (for "Phosphate transporter"), with specific isoforms referred to as PiT-1 (SLC20A1) and PiT-2 (SLC20A2))

The sodium-dependent phosphate transporter type III family comprises highly conserved and widely expressed integral membrane proteins responsible for the co-transport of inorganic phosphate and sodium ions into cells[1][2][3][4]. Human type III cotransporters include PiT-1 and PiT-2 (encoded by the SLC20A1 and SLC20A2 genes), which function primarily in cellular phosphate uptake vital for nucleotide synthesis, signal transduction, and skeletal mineralization. Mutations in these transporters, particularly PiT-2, are associated with familial brain calcification. Structurally, the transporter utilizes an elevator-like mechanism for sodium-phosphate symport, involving multiple sodium-binding sites critical for substrate specificity and translocation[1]. While no approved drugs directly target PiT-1 or PiT-2, their fundamental role in phosphate metabolism and disease positions them as significant research and potential therapeutic targets[1][2][3][4].

Other names

Sodium-dependent phosphate transporter type IIISodium/phosphate cotransporter type IIIPiT-1 (SLC20A1)PiT-2 (SLC20A2)Phosphate:Na+ symporter, type IIISLC20A1, SLC20A2

Inhibition of phosphate uptake by blocking transporter activity (research compounds) Indirect modulation via hormonal regulation (e.g., parathyroid hormone decreases expression/activity, though more prominent for SLC34 family)