Sodium-phosphate symporter which plays a fundamental housekeeping role in phosphate transport, such as absorbing phosphate from interstitial fluid for normal cellular functions such as cellular metabolism, signal transduction, and nucleic acid and lipid synthesis. May play a role in extracellular matrix and cartilage calcification as well as in vascular calcification. (Microbial infection) May function as a retroviral receptor but do not confer infection susceptibility to Gibbon Ape Leukemia Virus (GaLV), Simian sarcoma-associated virus (SSAV) and Feline leukemia virus subgroup B (FeLV-B). Ubiquitously expressed. Detected at 17 dpc of embryonic development in a subpopulation of early hypertrophic chondrocytes in bone, but not when fully differentiated. By growth hormone. Region A does not confer susceptibility to infection by Gibbon Ape Leukemia Virus (GaLV) and Feline leukemia virus subgroup B (FeLV-B). Substitution of Human SLC20A1 region A by region A of murine SLC20A1 prevents viral infection. Belongs to the inorganic phosphate transporter (PiT) (TC 2.A.20) family. Intron retention. The sequence differs at the 3'end due to intron retention.