Involved in actively transporting phosphate into cells via Na(+) cotransport in the renal brush border membrane (PubMed:7733319). The cotransport has a Na(+):Pi stoichiometry of 3:1 and is electrogenic (By similarity). 3 Na(+)(out) + phosphate(out) = 3 Na(+)(in) + phosphate(in) Transport activity is significantly increased in response to dietary phosphate deprivation. Interacts via its C-terminal region with PDZK2. Interacts with SLC9A3R1. Localized at the brush border membranes of the proximal tubules. Expressed in the kidney cortex. Up-regulated by a low-phosphate diet. Belongs to the SLC34A transporter family.