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CHIP regulates Aquaporin‐2 Quality Control and Body Water Homeostasis
Author(s) -
Wu Qi,
Moeller Hanne B.,
Stevens Donté A.,
SanchezHodge Rebekah,
Childers Gabrielle,
Kortenoeven Marleen L.A.,
Cheng Lei,
Rosenbaek Lena L.,
Rubel Carrie,
Patterson Cam,
Pisitkun Trairak,
Schisler Jonathan C.,
Fenton Robert A.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.624.1
Subject(s) - aquaporin 2 , gene knockdown , ubiquitin ligase , kidney , microbiology and biotechnology , biology , chemistry , endocrinology , ubiquitin , cell culture , water channel , biochemistry , gene , genetics , mechanical engineering , engineering , inlet
The importance of the kidney distal convoluted tubule (DCT) and cortical collecting duct (CCD) are highlighted by various water and electrolyte disorders that arise when the unique transport properties of these segments are disturbed. Despite this critical role, little is known about which proteins play a regulatory role in these cells and how these cells can be regulated by individual physiological stimuli. By combining proteomics, bioinformatics, and cell biology approaches alongside gene targeted animal models, we found an essential role of the E3 ubiquitin ligase CHIP for modulating the abundance of the water channel aquaporin‐2 (AQP2). CHIP is highly expressed throughout the collecting duct, modulated in abundance by vasopressin, interacts with AQP2, Hsp70 and Hsc70 and can directly ubiquitylate AQP2 in vitro . shRNA knockdown of CHIP in CCD cells increased AQP2 protein half‐life and reduced AQP2 ubiquitylation, resulting in greater AQP2 and phosphorylated AQP2 levels. Plasma membrane abundance of AQP2 was increased in CHIP knockdown cells. CHIP knockout mice or novel CRISPR/Cas9 mice without CHIP E3 ligase activity had greater AQP2 abundance and altered renal water handling, with decreased water intake and urine volume, alongside higher urine osmolality. No significant changes in other water or sodium transporting proteins were observed in the gene‐modified mice. In summary, CHIP has a regulatory role for AQP2 and subsequently renal water handling. Support or Funding Information Q.W. is supported by European Union Horizon 2020 Marie Skłodowska‐Curie Individual Fellowship project 705682, Danish Medical Research Council grant 6110‐00118B, and Lundbeck Foundation grant R192‐2015‐804. M.L.A.K. is supported by Danish Medical Research Council grant 1333‐00279. Funding is provided by National Institutes of Health grant R37 HL065619 (to C.P. and J.C.S.). Funding is also provided by the Novo Nordisk Foundation (R.A.F.), the Lundbeck Foundation (R.A.F.), and the Danish Medical Research Council (R.A.F.). This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .