aquaporin-2; AQP-2; Aquaporin-CD; AQP-CD; water channel protein for renal collecting duct; ADH water channel; collecting duct water channel protein; WCH-CD (AQP2)

Function

• forms a water-specific channel that provides plasma membranes of renal collecting duct with high permeability to water, permitting water to move in the direction of an osmotic gradient
• Ser-256 phosphorylation is necessary & sufficient for expression at the apical membrane
• endocytosis is not phosphorylation-dependent

Structure

• aquaporins contain two tandem repeats each containing 3 membrane-spanning domains & a pore-forming loop with the signature motif Asn-Pro-Ala (NPA)
• belongs to the MIP/aquaporin (TC 1.A.8) family

Compartment

• apical cell membrane
• cytoplasmic vesicle membrane
• shuttles from vesicles to the apical membrane

Expression

expressed in renal collecting tubules

Pathology

• defects in AQP2 are the cause of nephrogenic diabetes insipidus type 2

More general terms

• transmembrane 6 protein
• aquaporin
• phosphoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/P41181.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=359
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:359
• OMIM: https://mirror.omim.org/entry/107777
• OMIM: https://mirror.omim.org/entry/125800