The Highly Dynamic Nature of ERdj5 Is Key to Efficient Elimination of Aberrant Protein Oligomers through ER-Associated Degradation

Structure. 2017 Jun 6;25(6):846-857.e4. doi: 10.1016/j.str.2017.04.001. Epub 2017 May 4.

Abstract

ERdj5, composed of an N-terminal J domain followed by six thioredoxin-like domains, is the largest protein disulfide isomerase family member and functions as an ER-localized disulfide reductase that enhances ER-associated degradation (ERAD). Our previous studies indicated that ERdj5 comprises two regions, the N- and C-terminal clusters, separated by a linker loop and with distinct functional roles in ERAD. We here present a new crystal structure of ERdj5 with a largely different cluster arrangement relative to that in the original crystal structure. Single-molecule observation by high-speed atomic force microscopy visualized rapid cluster movement around the flexible linker loop, indicating the highly dynamic nature of ERdj5 in solution. ERdj5 mutants with a fixed-cluster orientation compromised the ERAD enhancement activity, likely because of less-efficient reduction of aberrantly formed disulfide bonds and prevented substrate transfer in the ERdj5-mediated ERAD pathway. We propose a significant role of ERdj5 conformational dynamics in ERAD of disulfide-linked oligomers.

Keywords: ERAD; ERdj5; X-ray crystal structure analysis; high-speed AFM; single-molecule analysis.

MeSH terms

  • Crystallography, X-Ray
  • Disulfides / chemistry
  • Disulfides / metabolism
  • Endoplasmic Reticulum-Associated Degradation / physiology*
  • HSP40 Heat-Shock Proteins / chemistry*
  • HSP40 Heat-Shock Proteins / genetics
  • HSP40 Heat-Shock Proteins / metabolism*
  • Heat-Shock Proteins / metabolism
  • Humans
  • Membrane Proteins / metabolism
  • Microscopy, Atomic Force
  • Models, Molecular
  • Molecular Chaperones / chemistry*
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism*
  • Mutation
  • Protein Conformation

Substances

  • DNAJC10 protein, human
  • Disulfides
  • EDEM1 protein, human
  • HSP40 Heat-Shock Proteins
  • Heat-Shock Proteins
  • Membrane Proteins
  • Molecular Chaperones
  • molecular chaperone GRP78