We have updated our privacy policy. If you have any question, contact us at privacy@scicrunch.org. Dismiss and don't show again

Searching across hundreds of databases

Our searching services are busy right now. Your search will reload in five seconds.

Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

Ubr1 and Ubr2 function in a quality control pathway for degradation of unfolded cytosolic proteins.

Quality control systems facilitate polypeptide folding and degradation to maintain protein homeostasis. Molecular chaperones promote folding, whereas the ubiquitin/proteasome system mediates degradation. We show here that Saccharomyces cerevisiae Ubr1 and Ubr2 ubiquitin ligases promote degradation of unfolded or misfolded cytosolic polypeptides. Ubr1 also catalyzes ubiquitinylation of denatured but not native luciferase in a purified system. This activity is based on the direct interaction of denatured luciferase with Ubr1, although Hsp70 stimulates polyubiquitinylation of the denatured substrate. We also report that loss of Ubr1 and Ubr2 function suppressed the growth arrest phenotype resulting from chaperone mutation. This correlates with increased protein kinase maturation and indicates partitioning of foldable conformers toward the proteasome. Our findings, based on the efficiency of this quality control system, suggest that the cell trades growth potential to avert the potential toxicity associated with accumulation of unfolded or misfolded proteins. Ubr1 and Ubr2 therefore represent E3 components of a novel quality control pathway for proteins synthesized on cytosolic ribosomes.

Pubmed ID: 20462952 RIS Download

Mesh terms: Animals | Cyclic AMP-Dependent Protein Kinases | HSP70 Heat-Shock Proteins | Luciferases, Firefly | Peptides | Proteasome Endopeptidase Complex | Proteasome Inhibitors | Protein Conformation | Protein Denaturation | Protein Folding | Saccharomyces cerevisiae | Saccharomyces cerevisiae Proteins | Ubiquitin-Protein Ligases | Ubiquitination | Unfolded Protein Response

Research resources used in this publication

None found

Research tools detected in this publication

Data used in this publication

None found

Associated grants

  • Agency: NCRR NIH HHS, Id: 5G12-RR03060
  • Agency: NCI NIH HHS, Id: U54CA132378
  • Agency: NCRR NIH HHS, Id: G12 RR003060
  • Agency: NCI NIH HHS, Id: U54 CA132378
  • Agency: NIGMS NIH HHS, Id: R01GM067785
  • Agency: NIGMS NIH HHS, Id: R01GM70596
  • Agency: NIGMS NIH HHS, Id: R01 GM070596
  • Agency: NIGMS NIH HHS, Id: R01 GM067785

Publication data is provided by the National Library of Medicine ® and PubMed ®. Data is retrieved from PubMed ® on a weekly schedule. For terms and conditions see the National Library of Medicine Terms and Conditions.

This is a list of tools and resources that we have found mentioned in this publication.