A tunable affinity fusion tag for protein self-assembly.

Area of Science:

• Cell Biology
• Biochemistry
• Synthetic Biology

Background:

• Cellular protein concentrations vary, impacting cell function.
• Limited tools exist to precisely control protein levels and study their effects.

Purpose of the Study:

• To develop a novel genetically encoded tool for precise control of protein concentration thresholds.
• To investigate the functional consequences of protein concentration variation in cells.

Main Methods:

• Screening of dipeptide repeats to identify suitable candidates for amyloid formation.
• Engineering a tunable amyloid system based on poly-threonine alanine (poly-TA).
• Demonstrating fine-tuning of poly-TA saturating concentration (C_sat) by adjusting repeat length.

Main Results:

• Identified poly-TA as an ideal candidate for forming amyloid-like assemblies with tunable nucleation barriers.
• Poly-TA allows for precise control over protein concentration thresholds.
• The C_sat of poly-TA can be modulated by altering the length of uninterrupted TA repeats.

Conclusions:

• The developed tunable amyloid tool provides a modular system for manipulating protein solubility.
• This tool facilitates the investigation of relationships between protein concentration, phase separation, and cellular function.
• Potential applications span cell biology, developmental biology, and synthetic biology.