The structural plasticity of polyglutamine repeats

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• Polyglutamine (polyQ) repeat tracts are prevalent in proteins across species, notably in transcription factor activation domains.
• These polymorphic motifs influence protein interactions and can lead to aberrant self-assembly.
• Expansion beyond critical lengths triggers pathological self-assembly.

Purpose of the Study:

• To review current knowledge on polyglutamine tract structures in soluble and aggregated states.
• To discuss the impact of neighboring regions on polyQ secondary structure, aggregation, and fibril morphology.
• To briefly address the influence of the genetic context of polyQ-encoding trinucleotides.

Main Methods:

• Literature review of structural and aggregation studies on polyglutamine tracts.
• Analysis of factors influencing polyQ secondary structure and fibril formation.
• Discussion of genetic context effects on polyQ expansion and aggregation.

Main Results:

• PolyQ tracts adopt diverse structures in soluble and aggregated forms.
• Neighboring protein regions significantly modulate polyQ tract secondary structure, aggregation propensity, and fibril morphology.
• The genetic context of polyQ-encoding trinucleotides presents challenges for understanding expansion and aggregation.

Conclusions:

• Understanding polyQ tract structure and aggregation is crucial for deciphering their role in health and disease.
• Neighboring sequences are key determinants of polyQ behavior, influencing both structure and aggregation.
• Further research into the genetic context of polyQ repeats is needed to fully address pathological implications.