Derlin-1 Overexpression Ameliorates Mutant SOD1-induced Endoplasmic Reticulum Stress by Reducing Mutant SOD1 Accumulation

Neurochem Int. 2011 Feb;58(3):344-53. doi: 10.1016/j.neuint.2010.12.010. Epub 2010 Dec 23.

Abstract

Unfolded protein responses, including induction of stress sensor kinases, chaperones, and apoptotic mediators, are involved in the familial amyotrophic lateral sclerosis (ALS) model related to mutant Cu/Zn superoxide dismutase (SOD1) and sporadic ALS. We hypothesized that the endoplasmic reticulum-resident factor Derlin-1 plays a pivotal role in the regulation of misfolded proteins evoked by mutant SOD1. We show that Derlin-1 overexpression reduced mutant SOD1-induced cell toxicity and increased cell viability by suppressing the activation of the ER stress pathway factors: immunoglobulin-binding protein, activating transcription factor 6 p50, and C/EBP homologous protein. Interestingly, exogenous Derlin-1 resulted in a decrease in the amount of mutant SOD1, and a lesser decrease in that of wild-type SOD1, in transfected cells. Reduced SOD1 protein expression was observed in the microsomal fraction of wild-type and mutant SOD1 cells. Our results indicate that Derlin-1 regulates the turn over of SOD1 by promoting the proteasomal and autophagosomal degradation of SOD1 protein, but not by decreasing mutant SOD1 mRNA levels. Insights into the effects of Derlin-1 on mutant SOD1 may facilitate advancements in the treatment of motor neuron degeneration associated with ALS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyotrophic Lateral Sclerosis / enzymology
  • Amyotrophic Lateral Sclerosis / genetics
  • Amyotrophic Lateral Sclerosis / metabolism*
  • Animals
  • Autophagy / genetics
  • Cell Line, Tumor
  • Down-Regulation / genetics
  • Endoplasmic Reticulum / enzymology
  • Endoplasmic Reticulum / metabolism*
  • Humans
  • Membrane Proteins / biosynthesis*
  • Membrane Proteins / genetics
  • Mice
  • Mutation / physiology
  • Neurons / enzymology
  • Neurons / metabolism*
  • Proteasome Endopeptidase Complex / metabolism
  • RNA, Messenger / biosynthesis
  • Stress, Physiological / genetics*
  • Superoxide Dismutase / antagonists & inhibitors
  • Superoxide Dismutase / genetics*
  • Superoxide Dismutase / metabolism
  • Superoxide Dismutase-1

Substances

  • Membrane Proteins
  • RNA, Messenger
  • SOD1 protein, human
  • derlin-1 protein, mouse
  • Sod1 protein, mouse
  • Superoxide Dismutase
  • Superoxide Dismutase-1
  • Proteasome Endopeptidase Complex