Rafoxanide and Closantel Inhibit SPAK and OSR1 Kinases by Binding to a Highly Conserved Allosteric Site on Their C-terminal Domains

ChemMedChem. 2017 May 9;12(9):639-645. doi: 10.1002/cmdc.201700077. Epub 2017 Apr 12.

Abstract

SPAK and OSR1 are two protein kinases that have emerged as attractive targets in the discovery of novel antihypertensive agents due to their role in regulating electrolyte balance in vivo. Herein we report the identification of an allosteric pocket on the highly conserved C-terminal domains of these two kinases, which influences their activity. We also show that some known WNK signaling inhibitors bind to this allosteric site. Using in silico screening, we identified the antiparasitic agent rafoxanide as a novel allosteric inhibitor of SPAK and OSR1. Collectively, this work will facilitate the rational design of novel SPAK and OSR1 kinase inhibitors that could be useful antihypertensive agents.

Keywords: OSR1; SPAK; allosteric inhibitors; hypertension; kinases.

MeSH terms

  • Allosteric Site
  • Amino Acid Sequence
  • Cholesterol / pharmacology*
  • Fluorescence Polarization
  • HEK293 Cells
  • Humans
  • Molecular Docking Simulation
  • Phosphorylation
  • Protein Binding
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / metabolism
  • Rafoxanide / pharmacology*

Substances

  • Protein Kinase Inhibitors
  • Rafoxanide
  • Cholesterol
  • OXSR1 protein, human
  • Protein Serine-Threonine Kinases
  • STK39 protein, human