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Efficient cell-specific uptake of binding proteins into the cytoplasm through engineered modular transport systems
Wouter P R Verdurmen1, Manuel Luginbühl1, Annemarie Honegger1
1Dept of Biochemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland.
Researchers developed a new assay to measure cytosolic delivery of proteins. They created modular transport systems using DARPins and bacterial toxins, successfully delivering proteins into the cytosol via anthrax pores and Pseudomonas exotoxin A.
Area of Science:
- Protein engineering
- Molecular biology
- Drug delivery
Background:
- Highly specific binding proteins offer therapeutic potential but face challenges in cytosolic delivery and measurement.
- Intracellular protein delivery is crucial for targeting cytoplasmic disease mechanisms.
Purpose of the Study:
- To develop a generic assay for quantifying cytosolic delivery.
- To engineer modular transport systems for efficient intracellular protein delivery.
Main Methods:
- Development of a biotin ligase-based assay for measuring cytosolic delivery.
- Construction of modular transport systems using designed ankyrin repeat proteins (DARPins) and bacterial toxin components.
- Evaluation of anthrax pores and Pseudomonas exotoxin A (ETA) translocation domains for DARPin delivery.
Main Results:
- The developed assay objectively quantifies cytosolic delivery.
- Both anthrax pores and ETA translocation domains efficiently deliver DARPins into the cytosol.
- Anthrax pores require cargo to be below a thermodynamic stability threshold, while ETA does not exhibit this restriction.
Conclusions:
- Modular transport systems can overcome cytosolic delivery barriers.
- The ETA translocation pathway offers a promising, potentially less restrictive, route for intracellular delivery of engineered proteins.
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