UT (Urea Transporter)
Reference work entry
Since 1934, it has been understood that urea plays a key role in the generation of concentrated urine (reviewed in Klein et al. 2011). Functional measurements of urea transport in the kidney inner medullary collecting duct (IMCD), performed in the 1980s, provided evidence for the existence of urea transporter proteins (reviewed in Klein et al. 2011). Currently, two families of urea transporters have been cloned: SLC14A1, the UT-B urea transporter originally isolated from erythrocytes; and SLC14A2, the UT-A group with six distinct isoforms described to date (reviewed in Klein et al. 2011) (Table 1). In the kidney, UT-A1 and UT-A3 are expressed in the IMCD; UT-A2 is expressed in the thin descending limb (tDL); and UT-B is located primarily in the descending vasa recta and red blood cells (Fig. 1). Although the exact location has yet to be determined, UT-A4 is expressed in rat kidney medulla but not in the...
- Blount MA, Cipriani P, Redd SK, Ordas RJ, Black LN, Gumina DL, et al. Activation of protein kinase Calpha increases phosphorylation of the UT-A1 urea transporter at serine 494 in the inner medullary collecting duct. Am J Physiol Cell Physiol. 2015;309:C608–15. doi:10.1152/ajpcell.00171.2014.CrossRefPubMedPubMedCentralGoogle Scholar
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- Klein JD, Wang Y, Blount MA, Molina PA, LaRocque LM, Ruiz JA, et al. Metformin, an AMPK activator, stimulates the phosphorylation of aquaporin 2 and urea transporter A1 in inner medullary collecting ducts. Am J Physiol Renal Physiol. 2016a;310:F1008–12. doi:10.1152/ajprenal.00102.2016.CrossRefPubMedPubMedCentralGoogle Scholar
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