DNA binding and mitotic phosphorylation protect polyglutamine proteins from assembly formation
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ABSTRACT: Polyglutamine expansion is associated with pathogenic protein aggregation in neurodegenerative disorders. However, long polyglutamine tracts are also found in many transcription factors (TFs), such as FOXP2, a TF implicated in human speech. Here, we explore how FOXP2 and other glutamine-rich TFs avoid unscheduled assembly. Throughout interphase, DNA binding, irrespective of sequence specificity, has a solubilizing effect. During mitosis, multiple phosphorylation events promote FOXP2’s eviction from chromatin and supplant the solubilizing function of DNA. Further, human-specific amino-acid substitutions linked to the evolution of speech map to a mitotic phospho-patch, the ‘EVO patch’, and reduce the propensity of the human FOXP2 to assemble. Fusing the pathogenic form of Huntingtin to either a DNA binding domain, a phospho-mimetic variant of this ‘EVO patch’ or a negatively charged peptide is sufficient to diminish assembly formation, suggesting that hijacking mechanisms governing solubility of glutamine-rich TFs may offer new strategies for treatment of polyQ expansion diseases.
ORGANISM(S): Homo sapiens
PROVIDER: GSE287132 | GEO | 2025/04/15
REPOSITORIES: GEO
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