SPAK and OSR1 Dependent Down-Regulation of Murine Renal Outer Medullary K⁺ Channel ROMK1

• DOI: 10.1159/000355812
• Publication Date: 2014-10-14T07:32:15Z
• Authors: Bernat Elvira; Carlos Munoz; Jose Borras; Hong Chen; Jamshed Warsi; Sumant Singh Ajay; Ekaterina Shumilina; Florian Lang
• Keywords: 570; Kidney Medulla; 0303 health sciences; Oxidative stress-responsive kinase 1; Patch-Clamp Techniques; Potassium Channels; K+ channel; 610; SPS1-related proline/alanine-rich kinase; Dermatology; Protein Serine-Threonine Kinases; Diseases of the genitourinary system. Urology; WNK; Mice; Xenopus laevis; 03 medical and health sciences; RL1-803; RC666-701; Oocytes; Renal tubule; Diseases of the circulatory (Cardiovascular) system; Animals; RC870-923; Potassium Channels, Inwardly Rectifying

<b><i>Background/Aims: </i></b>The kinases SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1) participate in the regulation of NaCl cotransporter NCC Na<sup>+</sup>,K<sup>+</sup>,2Cl<sup>-</sup> NKCC2. The are regulated by WNK (with-no-K[Lys]) kinases. Mutations genes encoding underly Gordon's syndrome, a monogenic disease leading to hypertension hyperkalemia. further regulate renal outer medullary K<sup>+</sup> channel ROMK1. present study explored, whether and/or have similarly potential modify activity <b><i>Methods: </i></b>ROMK1 was expressed <i>Xenopus</i> oocytes with or without additional expression wild-type SPAK, constitutively active <sup>T233E</sup>SPAK, catalytically inactive <sup>D212A</sup>SPAK, OSR1, <sup>T185E</sup>OSR1 <sup>D164A</sup>OSR1. Channel determined utilizing dual electrode voltage clamp ROMK1 protein abundance cell membrane chemiluminescence containing an extracellular hemagglutinin epitope (ROMK1-HA). <b><i>Results: ROMK1-HA were significantly down-regulated but not <sup>D212A</sup>SPAK. Similarly, <sup>T185E</sup>OSR1, <b><i>Conclusion: OSR1.