The SLC34 family are sometimes referred to as Type II sodium-phosphate co-transporters, alongside Type I (SLC17 family) and Type III (SLC20 family) transporters. Topological modelling suggests eight TM domains with C- and N- termini in the cytoplasm, and a re-entrant loop at TM7/8. SLC34 family members are expressed on the apical surfaces of epithelia in the intestine and kidneys to regulate body phosphate levels, principally NaPi-IIa and NaPi-IIb, respectively. NaPi-IIa and NaPi-IIb are electrogenic, while NaPiIIc is electroneutral [1].

These transporters can be inhibited by foscarnet, in contrast to type III sodium-phosphate cotransporters, the SLC20 family.

* 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]

* 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]

Murer H, Forster I, Biber J. (2004) The sodium phosphate cotransporter family SLC34. Pflugers Arch, 447 (5): 763-7. [PMID:12750889]

* 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]

* Wagner CA, Hernando N, Forster IC, Biber J. (2014) The SLC34 family of sodium-dependent phosphate transporters. Pflugers Arch, 466 (1): 139-53. [PMID:24352629]

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2. Banerjee S, Oza AM, Birrer MJ, Hamilton EP, Hasan J, Leary A, Moore KN, Mackowiak-Matejczyk B, Pikiel J, Ray-Coquard I et al.. (2018) Anti-NaPi2b antibody-drug conjugate lifastuzumab vedotin (DNIB0600A) compared with pegylated liposomal doxorubicin in patients with platinum-resistant ovarian cancer in a randomized, open-label, phase II study. Ann Oncol, 29 (4): 917-923. [PMID:29401246]

3. Dennis M, Rubinfeld B, Polakis P. (2013) Compositions and methods for the diagnosis and treatment of tumor. Patent number: US8535675 B2. Assignee: Genentech, Inc.. Priority date: 30/11/2009. Publication date: 17/09/2013.

4. Forster IC, Loo DD, Eskandari S. (1999) Stoichiometry and Na+ binding cooperativity of rat and flounder renal type II Na+-Pi cotransporters. Am J Physiol, 276 (4 Pt 2): F644-9. [PMID:10198426]

5. Maemoto M, Hirata Y, Hosoe S, Ouchi J, Narushima K, Akizawa E, Tsuji Y, Takada H, Yanagisawa A, Shuto S. (2022) Discovery of Gut-Restricted Small-Molecule Inhibitors of Intestinal Sodium-Dependent Phosphate Transport Protein 2b (NaPi2b) for the Treatment of Hyperphosphatemia. J Med Chem, 65 (3): 1946-1960. [PMID:35034442]