Table 1.

Tissue distribution and functions of aquaporin 5 in human body

System	Localization	Subcellular localization	Role	References
Digestive	Pancreas	AP of intercalated and intralobular duct cells; AP of mucoid gland/duct cells	Transcellular water flux for final isotonic pancreatic fluid production	[61]
	Salivary glands: lingual, labial, submandibular and parotid	AP of acinar cells; secretory canaliculi of submandibular and parotid glands	Transcellular water flux for primary saliva fluid production	[62, 63]
	Duodenum: Brunner’s glands	AP and BL of secretory cells	Water transport by the gland	[64]
Reproductive	Vagina	IN in epithelial cells	Transcellular water flux for vaginal lubrification	[54]
	Uterus	PM of smooth muscle cells; BL of glandular epithelial cells; glandular and luminal endometrial cells; stromal cells	Possible role in transepithelial water flux for uterine secretion and implantation	[55, 65]
Renal	Kidney (cortex)	AP of type B intercalated cells	Transepithelial water reabsorption in collecting system	[46]
Respiratory	Lung	AP of type I pneumocytes	Possible mediation of osmotic water permeability in type I alveolar cells	[47, 48]
	Airway sub-mucousal glands	AP of serous acinar cells	Water flow for surface liquid production and gland homeostasis	[47]
	Trachea	AP of columnar epithelial cells	Replenishment of evaporative losses and rapid restoration to a rehydrated state	[47]
	Bronchi	AP of ciliated duct columnar epithelial cells	Protection of the epithelia from evaporative dehydration and restoration of water from the submucosal vasculature	[47]
	Nasal cavity	AP of columnar epithelial cells facing the lumenal surface	Replenishment of evaporative losses and rapid restoration to a rehydrated state	[47, 49]
Integumentary	Sweat glands	AP and BL of secretory cells	Primary sweat fluid production	[50, 51, 66]
	Skin (stratum granulosum)	PM of keratinocytes	Skin hydration	[53]
	Mammary	AP of epithelial ductal cells	Transcellular water transport in milk production	[67, 68]
	Inner ear (cochlea)	AP of outer sulcus cells of the apical turn	transcellular water shunt mediation between the perilymph and endolymph	[58]
Senses	Eye (lens)	IN to PM of fibber cells depending on differentiation	Transparency maintenance of the corneal epithelium as well as underlying stroma; lens homeostasis	[60]
	Cornea	IN and PM corneal epithelial cell	Corneal fluid elimination	[56, 57, 59]
	Lacrimal glands	AP of acinar cells	Rapid water movement across lacrimal cell membranes	[66]

AP apical membrane, BL basolateral membrane, IN intracellular, PM plasma membrane