This is a family of mainly mammalian type II renal Na+/Pi-cotransporters with other related sequences from lower eukaryotes and bacteria some of which are also Na+/Pi-cotransporters. In the kidney the type II renal Na+/Pi-cotransporters protein allows re-absorption of filtered Pi in the proximal tubule [1].

1: Characterization of a murine type II sodium-phosphate cotransporter expressed in mammalian small intestine. Hilfiker H, Hattenhauer O, Traebert M, Forster I, Murer H, Biber J; Proc Natl Acad Sci U S A 1998;95:14564-14569. PMID:9826740