The high-affinity HSP90-CHIP complex recognizes and selectively degrades phosphorylated tau client proteins

J Clin Invest. 2007 Mar;117(3):648-58. doi: 10.1172/JCI29715. Epub 2007 Feb 15.

Abstract

A primary pathologic component of Alzheimer's disease (AD) is the formation of neurofibrillary tangles composed of hyperphosphorylated tau (p-tau). Expediting the removal of these p-tau species may be a relevant therapeutic strategy. Here we report that inhibition of Hsp90 led to decreases in p-tau levels independent of heat shock factor 1 (HSF1) activation. A critical mediator of this mechanism was carboxy terminus of Hsp70-interacting protein (CHIP), a tau ubiquitin ligase. Cochaperones were also involved in Hsp90-mediated removal of p-tau, while those of the mature Hsp90 refolding complex prevented this effect. This is the first demonstration to our knowledge that blockade of the refolding pathway promotes p-tau turnover through degradation. We also show that peripheral administration of a novel Hsp90 inhibitor promoted selective decreases in p-tau species in a mouse model of tauopathy, further suggesting a central role for the Hsp90 complex in the pathogenesis of tauopathies. When taken in the context of known high-affinity Hsp90 complexes in affected regions of the AD brain, these data implicate a central role for Hsp90 in the development of AD and other tauopathies and may provide a rationale for the development of novel Hsp90-based therapeutic strategies.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / metabolism*
  • Animals
  • Blood-Brain Barrier / metabolism
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Disease Models, Animal
  • Female
  • HSP90 Heat-Shock Proteins / antagonists & inhibitors
  • HSP90 Heat-Shock Proteins / genetics
  • HSP90 Heat-Shock Proteins / metabolism*
  • Heat Shock Transcription Factors
  • Humans
  • Male
  • Mice
  • Molecular Chaperones / metabolism*
  • Phosphorylation
  • Protein Folding
  • RNA, Small Interfering / pharmacology
  • Serine / metabolism
  • Tauopathies / metabolism*
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Ubiquitin-Protein Ligases / metabolism*
  • tau Proteins / metabolism*

Substances

  • DNA-Binding Proteins
  • HSF1 protein, human
  • HSP90 Heat-Shock Proteins
  • Heat Shock Transcription Factors
  • Molecular Chaperones
  • RNA, Small Interfering
  • Transcription Factors
  • tau Proteins
  • Serine
  • STUB1 protein, human
  • Ubiquitin-Protein Ligases