High-affinity sodium/citrate cotransporter that mediates the entry of citrate into cells, which is a critical participant of biochemical pathways (  , ). May function in various metabolic processes in which citrate has a critical role such as energy production (Krebs cycle), fatty acid synthesis, cholesterol synthesis, glycolysis, and gluconeogenesis . Transports citrate into the cell in a Na(+)-dependent manner, recognizing the trivalent form of citrate (physiological pH) rather than the divalent form (  , ). Can recognize succinate as a substrate, but its affinity for succinate is several fold lower than for citrate . The stoichiometry is probably 4 Na(+) for each carboxylate, irrespective of whether the translocated substrate is divalent or trivalent, rendering the process electrogenic (, ). Involved in the regulation of citrate levels in the brain (By similarity).
Subcellular locations: Cell membrane
Expressed most predominantly in the liver, with moderate expression detectable in the brain and testis.