Urea Transporter, Kidney (UTR)

In mammalian cells, urea is the chief end-product of nitrogen catabolism and plays an important role in the urinary concentration mechanism. Thus, the plasma membrane of erythrocytes and some renal epithelial cells exhibit an elevated urea permeability that is mediated by highly selective urea transporters. In mammals, 2 urea transporters have been identified: the renal tubular urea transporter, UT2, and the erythrocyte urea transporter, UT11 (SLC14A1). UTA1 has several putative phosphorylation sites within the intracellular domains, including 4 cAMP-dependent phosphorylation sites. Northern blot analysis detected transcripts of 6.5, 4.4, and 2.2 kb in the inner medulla but not in the cortex of human kidney. Western blot analysis detected endogenous UTA1 at an apparent molecular mass of 100 kD in human inner medulla.