Serine/threonine phosphatases and aquaporin-2 regulation in renal collecting duct

ABSTRACT: Phosphorylation of the aquaporin-2 (AQP2) water channel at four COOH-terminal serines plays a central role in the regulation of water permeability of the renal collecting duct. The level of phosphorylation at these sites is determined by a balance between phosphorylation by protein kinases and dephosphorylation by phosphatases. The phosphatases that dephosphorylate AQP2 have not been identified. Here, we use large-scale data integration techniques to identify serine-threonine phosphatases likely to interact with AQP2 in renal collecting duct principal cells. As a first step, we have created a comprehensive list of 38 S/T phosphatase catalytic subunits present in the mammalian genome. Then we used Bayes’ theorem to integrate available information from large-scale data sets from proteomic and transcriptomic studies in order to rank the known S/T phosphatases with regard to the likelihood that they interact with AQP2 in renal collecting duct cells. To broaden the analysis, we have generated new proteomic data (LC-MS/MS) identifying 4538 distinct proteins including 22 S/T phosphatases in cytoplasmic fractions from native inner medullary collecting duct cells from rats. The official gene symbols corresponding to the top-ranked phosphatases (common names in parentheses) were: Ppp1cb (PP1-beta), Ppm1g (PP2C), Ppp1ca (PP1-alpha), Ppp3ca (PP2-B or calcineurin), Ppp2ca (PP2A-alpha), Ppp1cc (PP1-gamma), Ppp2cb (PP2A-beta), Ppp6c (PP6C) and Ppp5c (PP5). This ranking correlates well with results of prior reductionist studies of ion and water channels in renal collecting duct cells.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Epithelial Cell, Kidney

SUBMITTER: Chung-Lin Chou  

LAB HEAD: Mark A. Knepper

PROVIDER: PXD005488 | Pride | 2018-10-26

REPOSITORIES: Pride