Urea transporters and aquaporins (Urea transporter (UT, specific isoforms include UT-A and UT-B); Aquaporin (AQP, specific isoforms include AQP1–AQP12))

Urea transporters are membrane proteins that facilitate the rapid, selective transport of urea across cell membranes along its concentration gradient. They are crucial for urine concentration in the kidney and are highly expressed in tissues like erythrocytes and renal medulla[7][8][9]. Two main types in mammals are UT-A (several isoforms, kidney-specific) and UT-B (erythrocytes, various tissues)[8][9][7]. Aquaporins are a diverse family of small, membrane-spanning water channels (AQP0–AQP12) that enable rapid and selective movement of water (and in some subfamilies, small solutes including glycerol and urea) across membranes[1][2][3][6][7]. These channels are critical for water homeostasis in organs such as the kidney, brain, eye, and secretory glands. Aquaglyceroporins (AQP3, 7, 9, and 10) can also transport urea and glycerol, which are important in energy metabolism and epidermal hydration[2][3][6][7]. Both families share similar roles in regulating osmotic balance but differ structurally and in substrate specificity; some AQPs have overlapping functions with UTs in urea transport, but the protein families are genetically and structurally distinct[7]. Disruption or dysregulation of either can contribute to a range of pathophysiological states, making them therapeutic targets for kidney disease, metabolic disorders, neuroinflammation, and cancer[3][6][9][1][7].

Other names

UTSLC14A familyUT-AUT-BAQPwater channelaquaglyceroporin

Inhibition of urea channels to limit renal concentration of urea, affecting urine concentration/pharmacokinetics; Inhibition/modulation of aquaporin-mediated water transport to address conditions of water imbalance; Possible modulation of CO₂/ammonia transport (future directions)