FunctionForms a channel with a broad specificity. Mediates passage of a wide variety of non-charged solutes including carbamides, polyols, purines, and pyrimidines in a phloretin- and mercury-sensitive manner, whereas amino acids, cyclic sugars, Na(+), K(+), Cl(-), and deprotonated monocarboxylates are excluded. Also permeable to urea and glycerol.
Tissue specificityHighly expressed in peripheral leukocytes. Also expressed in liver, lung, and spleen.
Sequence similaritiesBelongs to the MIP/aquaporin (TC 1.A.8) family.
DomainAquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA).