Enhanced tau pathology via RanBP9 and Hsp90/Hsc70 chaperone complexes.
Hum Mol Genet
; 26(20): 3973-3988, 2017 10 15.
Article
in En
| MEDLINE
| ID: mdl-29016855
ABSTRACT
Accumulation of amyloid ß (Aß) and tau represent the two major pathological hallmarks of Alzheimer's disease (AD). Despite the critical importance of Aß accumulation as an early event in AD pathogenesis, multiple lines of evidence indicate that tau is required to mediate Aß-induced neurotoxic signals in neurons. We have previously shown that the scaffolding protein Ran-binding protein 9 (RanBP9), which is highly elevated in brains of AD and AD mouse models, both enhances Aß production and mediates Aß-induced neurotoxicity. However, it is unknown whether and how RanBP9 transmits Aß-induced neurotoxic signals to tau. Here we show for the first time that overexpression or knockdown of RanBP9 directly enhances and reduces tau levels, respectively, in vitro and in vivo. Such changes in tau levels are associated with the ability of RanBP9 to physically interact with tau and heat shock protein 90/heat shock cognate 70 (Hsp90/Hsc70) complexes. Meanwhile, both RanBP9 and tau levels are simultaneously reduced by Hsp90 or Hsc70 inhibitors, whereas overexpression or knockdown of RanBP9 significantly diminishes the anti-tau potency of Hsp90/Hsc70 inhibitors as well as Hsc70 variants (WT & E175S). Further, RanBP9 increases the capacity for Hsp90 and Hsc70 complexes to bind ATP and enhances their ATPase activities in vitro. These observations in vitro and cell lines are recapitulated in primary neurons and in vivo, as genetic reduction in RanBP9 not only ameliorates tauopathy in Tau-P301S mice but also rescues the deficits in synaptic integrity and plasticity.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Nuclear Proteins
/
Tau Proteins
/
HSP90 Heat-Shock Proteins
/
Cytoskeletal Proteins
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Adaptor Proteins, Signal Transducing
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HSC70 Heat-Shock Proteins
Limits:
Animals
/
Humans
Language:
En
Journal:
Hum Mol Genet
Journal subject:
BIOLOGIA MOLECULAR
/
GENETICA MEDICA
Year:
2017
Document type:
Article