HERC3 facilitates ERAD of select membrane proteins by recognizing membrane-spanning domains

J Cell Biol. 2024 Jul 1;223(7):e202308003. doi: 10.1083/jcb.202308003. Epub 2024 May 9.

Abstract

Aberrant proteins located in the endoplasmic reticulum (ER) undergo rapid ubiquitination by multiple ubiquitin (Ub) E3 ligases and are retrotranslocated to the cytosol as part of the ER-associated degradation (ERAD). Despite several ERAD branches involving different Ub E3 ligases, the molecular machinery responsible for these ERAD branches in mammalian cells remains not fully understood. Through a series of multiplex knockdown/knockout experiments with real-time kinetic measurements, we demonstrate that HERC3 operates independently of the ER-embedded ubiquitin ligases RNF5 and RNF185 (RNF5/185) to mediate the retrotranslocation and ERAD of misfolded CFTR. While RNF5/185 participates in the ERAD process of both misfolded ABCB1 and CFTR, HERC3 uniquely promotes CFTR ERAD. In vitro assay revealed that HERC3 directly interacts with the exposed membrane-spanning domains (MSDs) of CFTR but not with the MSDs embedded in liposomes. Therefore, HERC3 could play a role in the quality control of MSDs in the cytoplasm and might be crucial for the ERAD pathway of select membrane proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
  • DNA-Binding Proteins
  • Endoplasmic Reticulum / metabolism
  • Endoplasmic Reticulum-Associated Degradation*
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Membrane Proteins* / chemistry
  • Membrane Proteins* / metabolism
  • Protein Binding
  • Protein Domains
  • Protein Folding
  • Ubiquitin-Protein Ligases* / genetics
  • Ubiquitin-Protein Ligases* / metabolism
  • Ubiquitination

Substances

  • HERC3 protein, human