Aquaporin-2 phospho S256
Domain
Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro-Ala (NPA).
Function
Forms a water-specific channel that provides the plasma membranes of renal collecting duct with high permeability to water, thereby permitting water to move in the direction of an osmotic gradient (PubMed:15509592, PubMed:7510718, PubMed:7524315, PubMed:8140421, PubMed:8584435). Plays an essential role in renal water homeostasis (PubMed:15509592, PubMed:7524315, PubMed:8140421). Could also be permeable to glycerol (PubMed:8584435).
Involvement in disease
Diabetes insipidus, nephrogenic, 2, autosomal
NDI2
A disorder caused by the inability of the renal collecting ducts to absorb water in response to arginine vasopressin. Characterized by excessive water drinking (polydipsia), excessive urine excretion (polyuria), persistent hypotonic urine, and hypokalemia. Inheritance can be autosomal dominant or recessive.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Ser-256 phosphorylation is necessary and sufficient for expression at the apical membrane. Endocytosis is not phosphorylation-dependent.
N-glycosylated.
Sequence Similarities
Belongs to the MIP/aquaporin (TC 1.A.8) family.
Tissue Specificity
Expressed in collecting tubules in kidney medulla (at protein level) (PubMed:7510718). Detected in kidney (PubMed:7510718).
Cellular localization
- Apical cell membrane
- Multi-pass membrane protein
- Basolateral cell membrane
- Multi-pass membrane protein
- Cell membrane
- Multi-pass membrane protein
- Cytoplasmic vesicle membrane
- Multi-pass membrane protein
- Golgi apparatus
- trans-Golgi network membrane
- Multi-pass membrane protein
- Shuttles from vesicles to the apical membrane (PubMed:15509592). Vasopressin-regulated phosphorylation is required for translocation to the apical cell membrane (PubMed:15509592). PLEKHA8/FAPP2 is required to transport AQP2 from the TGN to sites where AQP2 is phosphorylated (By similarity).
Alternative names
Aquaporin-2, AQP-2, ADH water channel, Aquaporin-CD, Collecting duct water channel protein, WCH-CD, Water channel protein for renal collecting duct, AQP-CD, AQP2