Hypertonicity-responsive ubiquitin ligase RNF183 promotes Na, K-ATPase lysosomal degradation through ubiquitination of its β1 subunit

Biochem Biophys Res Commun. 2020 Jan 22;521(4):1030-1035. doi: 10.1016/j.bbrc.2019.11.001. Epub 2019 Nov 13.


We previously reported that RNF183, a member of the RING finger (RNF) protein family, is specifically expressed in the renal collecting duct and that RNF183 mRNA is induced by the activity of nuclear factor of activated T cells 5 (NFAT5), which regulates the transcription of essential proteins for adaptation to hypertonic conditions. The renal medulla is the only tissue that is continuously hypertonic; therefore, RNF183 possibly plays an important role in adaptation to continuous hypertonic conditions. However, the mechanism of how cells adapt to long-term hypertonicity via RNF183 remains unclear. In this study, the Na, K-ATPase α1 subunit was identified as a candidate substrate of RNF183 by the BirA proximity-biotinylation technique. The Na, K-ATPase α1 subunit acts as an ion transporter along with the Na, K-ATPase β1 subunit at the plasma membrane. We confirmed that RNF183 interacted with both α1 and β1 subunits; however, we found that RNF183 ubiquitinated only the β1 subunit, not the α1 subunit. Furthermore, RNF183 translocated both α1 and β1 subunits from the plasma membrane to lysosomes. In addition, the expression levels of α1 and β1 subunits in HEK293 cells stably expressing RNF183 were significantly decreased compared with mock control cells, and were restored by siRNA-mediated knockdown of RNF183. Moreover, in RNF183-expressing cells, chloroquine treatment increased the protein levels of the α1 and β1 subunits. Therefore, our results suggest that Na, K-ATPase α1 and β1 subunits are degraded in lysosomes by RNF183-mediated ubiquitination of β1 subunit.

Keywords: BirA; Hypertonic stress; K-ATPase; Lysosome; Na; RNF183; Ubiquitin ligase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Hypertonic Solutions / pharmacology*
  • Lysosomes / drug effects
  • Lysosomes / metabolism
  • Mice
  • Protein Binding / drug effects
  • Protein Subunits / metabolism*
  • Protein Transport / drug effects
  • Proteolysis / drug effects
  • Sodium-Potassium-Exchanging ATPase / metabolism*
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination* / drug effects


  • ATP1B1 protein, human
  • Hypertonic Solutions
  • Protein Subunits
  • RNF183 protein, human
  • Ubiquitin-Protein Ligases
  • Sodium-Potassium-Exchanging ATPase