Coaggregation of polyglutamine(polyQ)proteins is mediated by polyQ-tract interactions and impairs cellular proteostasis  

作　　者：Jun-Ye Hong Jian-Yang Wang Hong-Wei Yue Xiang-Le Zhang Shu-Xian Zhang Lei-Lei Jiang Hong-Yu Hu 

机构地区：[1]State Key Laboratory of Molecular Biology,Shanghai Institute of Biochemistry and Cell Biology,Center for Excellence in Molecular Cell Science,Chinese Academy of Sciences,Shanghai 200031,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Acta Biochimica et Biophysica Sinica》2023年第5期736-748,共13页生物化学与生物物理学报（英文版）

基　　金：supported by the grants from the National Natural Science Foundation of China(Nos.31470758 and 31870764).

摘　　要：Nine polyglutamine(polyQ)proteins have already been identified that are considered to be associated with the pathologies of neurodegenerative disorders called polyQ diseases,but whether these polyQ proteins mutually interact and synergize in proteinopathies remains to be elucidated.In this study,4 polyQ-containing proteins,androgen receptor(AR),ataxin-7(Atx7),huntingtin(Htt)and ataxin-3(Atx3),are used as model molecules to investigate their heterologous coaggregation and consequent impact on cellular proteostasis.Our data indicate that the N-terminal fragment of polyQ-expanded(PQE)Atx7 or Htt can coaggregate with and sequester AR and Atx3 into insoluble aggregates or inclusions through their respective polyQ tracts.In vitro coprecipitation and NMR titration experiments suggest that this specific coaggregation depends on polyQ lengths and is probably mediated by polyQtract interactions.Luciferase reporter assay shows that these coaggregation and sequestration effects can deplete the cellular availability of AR and consequently impair its transactivation function.This study provides valid evidence supporting the viewpoint that coaggregation of polyQ proteins is mediated by polyQ-tract interactions and benefits our understanding of the molecular mechanism underlying the accumulation of different polyQ proteins in inclusions and their copathological causes of polyQ diseases.

关 键 词：POLYGLUTAMINE COAGGREGATION protein interaction PROTEOSTASIS SEQUESTRATION 

分 类 号：Q51[生物学—生物化学]