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 leaves and at lower levels in roots. 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.