PolyQ-expanded proteins impair cellular proteostasis of ataxin-3 through sequestering the co-chaperone HSJ1 into aggregates

Polyglutamine (polyQ) expansion of proteins can trigger protein misfolding and amyloid-like aggregation, which thus lead to severe cytotoxicities and even the respective neurodegenerative diseases. However, why polyQ aggregation is toxic to cells is not fully elucidated. Here, we took the fragments of polyQ-expanded (PQE) ataxin-7 (Atx7) and huntingtin (Htt) as models to investigate the effect of polyQ aggregates on the cellular proteostasis of endogenous ataxin-3 (Atx3), a protein that frequently appears in diverse inclusion bodies. We found that PQE Atx7 and Htt impair the cellular proteostasis of Atx3 by reducing its soluble as well as total Atx3 level but enhancing formation of the aggregates. Expression of these polyQ proteins promotes proteasomal degradation of endogenous Atx3 and accumulation of its aggregated form. Then we verified that the co-chaperone HSJ1 is an essential factor that orchestrates the balance of cellular proteostasis of Atx3; and further discovered that the polyQ proteins can sequester HSJ1 into aggregates or inclusions in a UIM domain-dependent manner. Thereby, the impairment of Atx3 proteostasis may be attributed to the sequestration and functional loss of cellular HSJ1. This study deciphers a potential mechanism underlying how PQE protein triggers proteinopathies, and also provides additional evidence in supporting the hijacking hypothesis that sequestration of cellular interacting partners by protein aggregates leads to cytotoxicity or neurodegeneration.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:11

Enthalten in:

Scientific reports - 11(2021), 1 vom: 09. Apr., Seite 7815

Sprache:

Englisch

Beteiligte Personen:

Yue, Hong-Wei [VerfasserIn]
Hong, Jun-Ye [VerfasserIn]
Zhang, Shu-Xian [VerfasserIn]
Jiang, Lei-Lei [VerfasserIn]
Hu, Hong-Yu [VerfasserIn]

Links:

Volltext

Themen:

26700-71-0
ATXN3 protein, human
Amyloid
Amyloidogenic Proteins
Ataxin-3
DNAJB2 protein, human
EC 3.4.19.12
EC 3.4.25.1
HSP40 Heat-Shock Proteins
HTT protein, human
Huntingtin Protein
Journal Article
Molecular Chaperones
Peptides
Polyglutamine
Proteasome Endopeptidase Complex
Protein Aggregates
Repressor Proteins
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 08.11.2021

Date Revised 08.11.2021

published: Electronic

Citation Status MEDLINE

doi:

10.1038/s41598-021-87382-w

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM323923291