A common mechanism of PLP/DM20 misfolding causes cysteine-mediated endoplasmic reticulum retention in oligodendrocytes and Pelizaeus-Merzbacher disease

Proc Natl Acad Sci U S A. 2007 Nov 6;104(45):17813-8. doi: 10.1073/pnas.0704975104. Epub 2007 Oct 25.

Abstract

A large number of mutations in the human PLP1 gene lead to abnormal myelination and oligodendrocyte death in Pelizaeus-Merzbacher disease (PMD). Here we show that a major subgroup of PMD mutations that map into the extracellular loop region of PLP/DM20 leads to the failure of oligodendrocytes to form the correct intramolecular disulfide bridges. This leads to abnormal protein cross-links and endoplasmic reticulum retention and activates the unfolded protein response. Importantly, surface expression of mutant PLP/DM20 can be restored and the unfolded protein response can be reverted by the removal of two cysteines. Thus, covalent protein cross-links emerge as a cause, rather than as a consequence, of endoplasmic reticulum retention.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Binding Sites
  • Cysteine / physiology*
  • Endoplasmic Reticulum / pathology*
  • Gene Expression Regulation
  • Humans
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Models, Molecular
  • Myelin Proteolipid Protein / chemistry
  • Myelin Proteolipid Protein / genetics*
  • Myelin Proteolipid Protein / metabolism
  • Oligodendroglia / pathology*
  • Pelizaeus-Merzbacher Disease / genetics*
  • Pelizaeus-Merzbacher Disease / pathology*
  • Protein Conformation
  • Protein Folding

Substances

  • Membrane Proteins
  • Myelin Proteolipid Protein
  • PLP1 protein, human
  • Cysteine