Aquaporins: Small Proteins with Diverse Functions

It is a well known fact that aquaporins are the small protein channels responsible for the water and salt homeostasis. They are widely distributed in plants, lower organisms and mammals. In addition to the role in water homeostasis they also serve many other important physiological functions and their malfunction may result in many pathological disorders. Present review will add a new dimension to the knowledge of this small protein molecule in various physiological phenomenon such as secretion of glands, neuroexcitation, fat metabolism, cell migration, cell proliferation, hydration of skin, tumor angiogenesis, wound healing and glial scar formation. Transport of water and other molecules such as glycerol and ammonia are responsible for various functions served by aquaporins. Deficiency or absence of aquaporin leads to various pathological disorders such as congenital cataracts and neuromyelitisoptica. They also play role in development of brain edema and obstructive hydrocephalus. Moreover they can be the site of targeted drug therapy in many pathological processes. Disorders such as brain edema, epilepsy, obesity and cancer can be treated by altering the expression of aquaporins on various tissues.