Dissecting the ER-Associated Degradation of a Misfolded Polytopic Membrane Protein

Kunio Nakatsukasa, Gregory Huyer, Susan Michaelis, Jeffrey L. Brodsky

Research output: Contribution to journalArticlepeer-review

Abstract

It remains unclear how misfolded membrane proteins are selected and destroyed during endoplasmic reticulum-associated degradation (ERAD). For example, chaperones are thought to solubilize aggregation-prone motifs, and some data suggest that these proteins are degraded at the ER. To better define how membrane proteins are destroyed, the ERAD of Ste6p*, a 12 transmembrane protein, was reconstituted. We found that specific Hsp70/40s act before ubiquitination and facilitate Ste6p* association with an E3 ubiquitin ligase, suggesting an active role for chaperones. Furthermore, polyubiquitination was a prerequisite for retrotranslocation, which required the Cdc48 complex and ATP. Surprisingly, the substrate was soluble, and extraction was independent of a ubiquitin chain extension enzyme (Ufd2p). However, Ufd2p increased the degree of ubiquitination and facilitated degradation. These data indicate that polytopic membrane proteins can be extracted from the ER, and define the point of action of chaperones and the requirement for Ufd2p during membrane protein quality control.

Original languageEnglish (US)
Pages (from-to)101-112
Number of pages12
JournalCell
Volume132
Issue number1
DOIs
StatePublished - Jan 11 2008

Keywords

  • CELLBIO
  • PROTEINS

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Fingerprint

Dive into the research topics of 'Dissecting the ER-Associated Degradation of a Misfolded Polytopic Membrane Protein'. Together they form a unique fingerprint.

Cite this