Electroneutral antiporter that translocates urate across the apical membrane of proximal tubular cells in exchange for monovalent organic or inorganic anions ( , ). Involved in renal reabsorption of urate and helps maintaining blood levels of uric acid (, ). Mediates urate uptake by an exchange with organic anions such as (S)-lactate and nicotinate, and inorganic anion Cl(-) . Other inorganic anions such as Br(-), I(-) and NO3(-) may also act as counteranions that exchange for urate . Also mediates orotate tubular uptake coupled with nicotinate efflux and to a lesser extent with lactate efflux, therefore displaying a potential role in orotate renal reabsorption . Orotate transport is Cl(-)-dependent .
Subcellular locations: Apical cell membrane
Detected in kidney (at protein level). Detected in fetal and adult kidney. Detected in epithelial cells of proximal tubules in renal cortex.