Abstract
Discovery of the Aquaporin Water Channels provided the molecular explanation for rapid uptake or release of water from the plasma membranes of multiple tissues. Constitutively active water permeation is ascribed to AQP1 in red cells and renal proximal tubules. Vasopressin regulated water permeation occurs in collecting duct principal cells where AQP2 is shuttled to the apical surface in response to thirsting or blood loss. Humans have a repertoire of other aquaporins: AQP4 in brain and AQP5 in secretory glands. Aquaglyceroporin AQP3 confers high water and glycerol release by basal level of skin: AQP7 in adipocytes and AQP9 in hepatocytes. Microbes express aquaporins or aquaglyceroporins. Malaria parasites express a single PfAQP that is permeated by water and glycerol and is required for full virulence. Field studies of malaria are underway.
