AVPR2 and AQP2
AVPR2 and AQP2 AVPR2 belongs to the family of G-protein coupled cell surface receptors, which are typically composed of three distinct domains: an extracellular domain; a transmembrane domain, which traverses the membrane seven times; and a cytoplasmic domain. Upon binding of vasopressin to the extracellular domain, a GTP-binding protein (G protein) in contact with the cytoplasmic face of the AVPR2 molecule becomes activated. The activated G protein stimulates adenylyl cyclase to produce cyclic adenosine monophosphate (cAMP). cAMP then acts as a “second messenger“ within the cell, triggering an increase in the number of AQP2 molecules present in the cell membrane. In the short term, this increase is achieved through the incorporation of “pre-made” AQP2 molecules, stored in vesicles within the cytoplasm, into the cell membrane. In the long term, an increase in the number of available AQP2 molecules is induced, probably through stimulation of AQP2 gene transcription (5).
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