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Bri2 BRICHOS client specificity and chaperone activity are governed by assembly state.

Gefei ChenAxel AbeleinHarriet E NilssonAxel LeppertYuniesky Andrade-TalaveraSimone TambaroLovisa HemmingssonFiroz RoshanMichael LandrehHenrik BiverstålPhilip J B KoeckJenny PrestoHans HebertAndré FisahnJan Johansson
Published in: Nature communications (2017)
Protein misfolding and aggregation is increasingly being recognized as a cause of disease. In Alzheimer's disease the amyloid-β peptide (Aβ) misfolds into neurotoxic oligomers and assembles into amyloid fibrils. The Bri2 protein associated with Familial British and Danish dementias contains a BRICHOS domain, which reduces Aβ fibrillization as well as neurotoxicity in vitro and in a Drosophila model, but also rescues proteins from irreversible non-fibrillar aggregation. How these different activities are mediated is not known. Here we show that Bri2 BRICHOS monomers potently prevent neuronal network toxicity of Aβ, while dimers strongly suppress Aβ fibril formation. The dimers assemble into high-molecular-weight oligomers with an apparent two-fold symmetry, which are efficient inhibitors of non-fibrillar protein aggregation. These results indicate that Bri2 BRICHOS affects qualitatively different aspects of protein misfolding and toxicity via different quaternary structures, suggesting a means to generate molecular chaperone diversity.
Keyphrases
  • protein protein
  • amino acid
  • oxidative stress
  • binding protein
  • small molecule
  • magnetic resonance imaging
  • high resolution
  • early onset
  • heat shock protein
  • computed tomography
  • cognitive decline
  • brain injury