Rsp5/Nedd4 Is the Main Ubiquitin Ligase That Targets Cytosolic Misfolded Proteins Following Heat Stress

Nat Cell Biol. 2014 Dec;16(12):1227-37. doi: 10.1038/ncb3054. Epub 2014 Oct 26.

Abstract

The heat-shock response is a complex cellular program that induces major changes in protein translation, folding and degradation to alleviate toxicity caused by protein misfolding. Although heat shock has been widely used to study proteostasis, it remained unclear how misfolded proteins are targeted for proteolysis in these conditions. We found that Rsp5 and its mammalian homologue Nedd4 are important E3 ligases responsible for the increased ubiquitylation induced by heat stress. We determined that Rsp5 ubiquitylates mainly cytosolic misfolded proteins upon heat shock for proteasome degradation. We found that ubiquitylation of heat-induced substrates requires the Hsp40 co-chaperone Ydj1 that is further associated with Rsp5 upon heat shock. In addition, ubiquitylation is also promoted by PY Rsp5-binding motifs found primarily in the structured regions of stress-induced substrates, which can act as heat-induced degrons. Our results support a bipartite recognition mechanism combining direct and chaperone-dependent ubiquitylation of misfolded cytosolic proteins by Rsp5.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Crystallography, X-Ray
  • Endosomal Sorting Complexes Required for Transport / genetics*
  • Endosomal Sorting Complexes Required for Transport / metabolism*
  • HSP40 Heat-Shock Proteins / metabolism*
  • HeLa Cells
  • Heat-Shock Response / physiology*
  • Hot Temperature
  • Humans
  • Mice
  • Nedd4 Ubiquitin Protein Ligases
  • Peptide Termination Factors / metabolism
  • Protein Folding*
  • Protein Structure, Tertiary
  • Pyruvate Decarboxylase / metabolism
  • Pyruvate Kinase / genetics
  • Pyruvate Kinase / metabolism
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Ubiquitin / metabolism
  • Ubiquitin-Protein Ligase Complexes / genetics*
  • Ubiquitin-Protein Ligase Complexes / metabolism
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination

Substances

  • Endosomal Sorting Complexes Required for Transport
  • HSP40 Heat-Shock Proteins
  • Peptide Termination Factors
  • SUP45 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Ubiquitin
  • YDJ1 protein, S cerevisiae
  • Ubiquitin-Protein Ligase Complexes
  • HUL5 protein, S cerevisiae
  • Nedd4 Ubiquitin Protein Ligases
  • Nedd4 protein, human
  • Nedd4l protein, mouse
  • Ubiquitin-Protein Ligases
  • Pyruvate Kinase
  • PDC1 protein, S cerevisiae
  • Pyruvate Decarboxylase
  • RSP5 protein, S cerevisiae