Module 3: Figure aquaporin structure
Aquaporin structure and functional organization.
The domain structure of a typical aquaporin is shown at the top. These domains come together to form one of the subunits (bottom left), which associate as tetramers to form a functional water channel (bottom right). Cyclic AMP-dependent phosphorylation of Ser-256 on the cytoplasmic C-terminal tail plays a critical role in the translocation of aquaporin-containing vesicles to the plasma membrane during the action of vasopressin (Module 7: collecting duct function).