Aquaporins facilitate the transport of water and small neutral solutes across cell membranes. May be involved in transport from the vacuolar compartment to the cytoplasm (By similarity). Tonoplast. Expressed in roots and leaves. By osmotic stress and abscisic acid (ABA). Down-regulated by chilling. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA). Belongs to the MIP/aquaporin (TC 1.A.8) family. TIP (TC 1.A.8.10) subfamily.