The ubiquitin ligase ZNRF1 promotes caveolin-1 ubiquitination and degradation to modulate inflammation

Nat Commun. 2017 Jun 8:8:15502. doi: 10.1038/ncomms15502.

Abstract

Caveolin-1 (CAV1), the major constituent of caveolae, plays a pivotal role in various cellular biological functions, including cancer and inflammation. The ubiquitin/proteasomal pathway is known to contribute to the regulation of CAV1 expression, but the ubiquitin ligase responsible for CAV1 protein stability remains unidentified. Here we reveal that E3 ubiquitin ligase ZNRF1 modulates CAV1 protein stability to regulate Toll-like receptor (TLR) 4-triggered immune responses. We demonstrate that ZNRF1 physically interacts with CAV1 in response to lipopolysaccharide and mediates ubiquitination and degradation of CAV1. The ZNRF1-CAV1 axis regulates Akt-GSK3β activity upon TLR4 activation, resulting in enhanced production of pro-inflammatory cytokines and inhibition of anti-inflammatory cytokine IL-10. Mice with deletion of ZNRF1 in their hematopoietic cells display increased resistance to endotoxic and polymicrobial septic shock due to attenuated inflammation. Our study defines ZNRF1 as a regulator of TLR4-induced inflammatory responses and reveals another mechanism for the regulation of TLR4 signalling through CAV1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caveolin 1 / chemistry
  • Caveolin 1 / metabolism*
  • Cecum / pathology
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Gene Deletion
  • Glycogen Synthase Kinase 3 beta / metabolism
  • Inflammation / metabolism*
  • Inflammation / pathology*
  • Inflammation Mediators / metabolism
  • Ligation
  • Lipopolysaccharides
  • Lysine / metabolism
  • Macrophages / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Protein Binding
  • Protein Stability
  • Proteolysis*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Punctures
  • RAW 264.7 Cells
  • Shock, Septic / immunology
  • Shock, Septic / metabolism
  • Shock, Septic / pathology
  • Signal Transduction
  • Toll-Like Receptor 4 / metabolism
  • Ubiquitin-Protein Ligases / deficiency
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination*

Substances

  • Caveolin 1
  • Cyclic AMP Response Element-Binding Protein
  • Inflammation Mediators
  • Lipopolysaccharides
  • Toll-Like Receptor 4
  • Ubiquitin-Protein Ligases
  • ZNRF1 protein, mouse
  • Glycogen Synthase Kinase 3 beta
  • Proto-Oncogene Proteins c-akt
  • Lysine