Depletion of vacuolar protein sorting-associated protein 35 is associated with increased lysosomal degradation of aquaporin-2.

Depletion of vacuolar protein sorting-associated protein 35 is associated with increased lysosomal degradation of aquaporin-2. Am J Physiol Renal Physiol. 2016 Oct 12;:ajprenal.00307.2016 Authors: Lee MS, Choi HJ, Park EJ, Park HJ, Kwon TH Abstract Carboxyl-terminus of AQP2 (AQP2c) undergoes post-translational modifications, including phosphorylation and ubiquitination, for the regulation of aquaporin-2 (AQP2) translocation and protein abundance. We aimed to identify novel proteins interacting with AQP2c. Recombinant AQP2c protein was made in E. coli BL21 (DE3) by exploiting the pET32 TrxA fusion system. Lysates of rat kidney inner medullary collecting duct (IMCD) tubule suspensions interacted with rat AQP2c bound to Ni(2+)-resin were subjected to LC-MS/MS proteomic analysis. Potential interacting proteins were identified, including vacuolar protein sorting-associated protein 35 (Vps35). Co-immunoprecipitation assay demonstrated that Vps35 interacted with AQP2c. Immunohistochemistry of rat kidney revealed that AQP2 and Vps35 were partly co-localized at the intracellular vesicles in the collecting duct cells. The role of Vps35 in the dDAVP-induced AQP2 regulation was examined in mpkCCDc14 cells. Cell surface biotinylation assay demonstrated that dDAVP-induced apical translocation of AQP2 was significantly decreased under the siRNA-mediated Vps35 knockdown. dDAVP-induced AQP2 up-regulation was less prominent in the cells with Vps35 kno...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research