Investigation of regulatory mechanisms of WNK signal by insulin

2015 Fiscal Year Final Research Report

• Project/Area Number: 26860628
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Kidney internal medicine
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: Nishida Hidenori 東京医科歯科大学, 医歯(薬)学総合研究科, 非常勤講師 (40707379)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 塩分感受性高血圧 / WNK / KLHL3 / インスリン / 質量分析

Outline of Final Research Achievements

Mutations in WNK1, WNK4, KLHL3, and Cullin3 result in an inherited hypertensive disease, pseudohypoaldosteronism type II. WNK activates the Na-Cl cotransporter (NCC) in the kidney. Further, KLHL3 binds to WNKs as an adapter protein of Cullin3-based E3 ubiquitin ligase and degrades them. Insulin have been identified as powerful activator of WNK signaling. In this study, we investigated effects of Akt, key downstream substrates of insulin, on KLHL3. Mass spectrometry analysis revealed KLHL3 phosphorylation at S433. Phospho-specific antibody demonstrated defective binding between phosphorylated KLHL3 and WNK4. in vitro kinase assay demonstrated that Akt can phosphorylate KLHL3 at S433. Insulin also increased phosphorylation of KLHL3 at S433 in cultured cells. This could be a novel mechanism on how insulin physiologically activate the WNK signal.

Free Research Field

腎臓内科学