Intracellular location of aquaporin-2 serine 269 phosphorylation and dephosphorylation in kidney collecting duct cells.

Intracellular location of aquaporin-2 serine 269 phosphorylation and dephosphorylation in kidney collecting duct cells. Am J Physiol Renal Physiol. 2020 Aug 17;: Authors: Wong KY, Wang WL, Su SH, Liu CF, Yu MJ Abstract Aquaporin-2 (AQP2) is a vasopressin-regulated water channel protein responsible for water reabsorption by the kidney collecting ducts. Under control conditions, most AQP2 resides in the recycling endosomes of the principal cells where it answers to vasopressin with trafficking to the apical plasma membrane to increase water reabsorption. Upon vasopressin withdrawal, apical AQP2 retreats to the early endosomes before joining the recycling endosomes for the next vasopressin stimulation. Prior studies have demonstrated a role of AQP2 S269 phosphorylation in reducing AQP2 endocytosis thereby prolonging apical AQP2 retention. Here, we studied where in the cells S269 was phosphorylated and dephosphorylated in response to vasopressin versus withdrawal. In the mpkCCD collecting cells, Vps35 knockdown slowed vasopressin-induced apical AQP2 trafficking resulting in AQP2 accumulation in the recycling endosomes where S269 was phosphorylated. Rab7 knockdown that impaired AQP2 trafficking from the early to the recycling endosomes reduced vasopressin-induced S269 phosphorylation. Rab5 knockdown that impaired AQP2 endocytosis did not affect vasopressin-induced S269 phosphorylation. Upon vasopressin withdrawal, S269 was not dephosphory...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research