The SLC20 family is looked upon not only as ion transporters, but also as retroviral receptors. As ion transporters, they are sometimes referred to as Type III sodium-phosphate co-transporters, alongside Type I (SLC17 family) and Type II (SLC34 family). PiTs are cell-surface transporters, composed of ten TM domains with extracellular C- and N-termini. PiT1 is a focus for dietary phosphate and vitamin D regulation of parathyroid hormone secretion from the parathyroid gland. PiT2 appears to be involved in intestinal absorption of dietary phosphate.

* Key recommended reading is highlighted with an asterisk

* Biber J, Hernando N, Forster I. (2013) Phosphate transporters and their function. Annu Rev Physiol, 75: 535-50. [PMID:23398154]

Collins JF, Bai L, Ghishan FK. (2004) The SLC20 family of proteins: dual functions as sodium-phosphate cotransporters and viral receptors. Pflugers Arch, 447 (5): 647-52. [PMID:12759754]

* Forster IC, Hernando N, Biber J, Murer H. (2013) Phosphate transporters of the SLC20 and SLC34 families. Mol Aspects Med, 34 (2-3): 386-95. [PMID:23506879]

Marks J, Debnam ES, Unwin RJ. (2010) Phosphate homeostasis and the renal-gastrointestinal axis. Am J Physiol Renal Physiol, 299 (2): F285-96. [PMID:20534868]

Miyamoto K, Haito-Sugino S, Kuwahara S, Ohi A, Nomura K, Ito M, Kuwahata M, Kido S, Tatsumi S, Kaneko I et al.. (2011) Sodium-dependent phosphate cotransporters: lessons from gene knockout and mutation studies. J Pharm Sci, 100 (9): 3719-30. [PMID:21567407]

* Shobeiri N, Adams MA, Holden RM. (2014) Phosphate: an old bone molecule but new cardiovascular risk factor. Br J Clin Pharmacol, 77 (1): 39-54. [PMID:23506202]

Virkki LV, Biber J, Murer H, Forster IC. (2007) Phosphate transporters: a tale of two solute carrier families. Am J Physiol Renal Physiol, 293 (3): F643-54. [PMID:17581921]

1. Ravera S, Virkki LV, Murer H, Forster IC. (2007) Deciphering PiT transport kinetics and substrate specificity using electrophysiology and flux measurements. Am J Physiol, Cell Physiol, 293 (2): C606-20. [PMID:17494632]