Conformational modulation mediated by polyglutamine expansion in CAG repeat expansion disease-associated proteins.

By Verani, Margherita; Bustamante, Maria; Martufi, Paola; Daldin, Manuel; Cariulo, Cristina; Azzollini, Lucia; Fodale, Valentina; Puglisi, Francesca; Weiss, Andreas; MacDonald, Douglas; et al
From Biochemical and Biophysical Research Communications (2016), 478(2), 949-955. Language: English, Database: CAPLUS, DOI:10.1016/j.bbrc.2016.08.057

We have previously reported TR-FRET based immunoassays to detect a conformational change imparted on huntingtin protein by the polyglutamine expansion, which we confirmed using biophys. methodologies. Using these immunoassays, we now report that polyglutamine expansion influences the conformational properties of other polyglutamine disease proteins, exemplified by the androgen receptor (assocd. with spinal bulbar muscular atrophy) and TATA binding protein (assocd. with spinocerebellar ataxia 17). Using artificial constructs bearing short or long polyglutamine expansions or a multimerized, unrelated epitope (mimicking the increase in anti-polyglutamine antibody epitopes present in polyglutamine repeats of increasing length) we confirmed that the conformational TR-FRET based immunoassay detects an intrinsic conformational property of polyglutamine repeats. The TR-FRET based conformational immunoassay may represent a rapid, scalable tool to identify modulators of polyglutamine-mediated conformational change in different proteins assocd. with CAG triplet repeat disorders.