Channel protein for glycerol. Has a role in both glycerol influx and efflux. Plays a role in osmoregulation: under osmotic stress the channel is apparently closed to allow accumulation of glycerol in the cell under hyperosmotic conditions. Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro/Leu-Ala/Ser (NPA). Present with 907 molecules/cell in log phase SD medium. Belongs to the MIP/aquaporin (TC 1.A.8) family.