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Updated: Apr 25, 2026
High-throughput Screening for Protein-based Inheritance in S. cerevisiae
Published on: August 8, 2017
Prion propagation can occur in a prokaryote and requires the ClpB chaperone
Andy H Yuan1, Sean J Garrity2, Entela Nako2
1Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States Whitehead Institute for Biomedical Research, Cambridge, United States.
Abstract:
Prions are self-propagating protein aggregates that are characteristically transmissible. In mammals, the PrP protein can form a prion that causes the fatal transmissible spongiform encephalopathies. Prions have also been uncovered in fungi, where they act as heritable, protein-based genetic elements. We previously showed that the yeast prion protein Sup35 can access the prion conformation in Escherichia coli. Here, we demonstrate that E. coli can propagate the Sup35 prion under conditions that do not permit its de novo formation. Furthermore, we show that propagation requires the disaggregase activity of the ClpB chaperone. Prion propagation in yeast requires Hsp104 (a ClpB ortholog), and prior studies have come to conflicting conclusions about ClpB's ability to participate in this process. Our demonstration of ClpB-dependent prion propagation in E. coli suggests that the cytoplasmic milieu in general and a molecular machine in particular are poised to support protein-based heredity in the bacterial domain of life.
Insights
This study shows that the bacteria Escherichia coli can propagate prion proteins, like the yeast Sup35 prion. This prion propagation requires the ClpB chaperone, suggesting protein-based heredity in bacteria.
Area of Science:
- Molecular Biology
- Protein Biochemistry
- Microbiology
Background:
- Prions are transmissible, self-propagating protein aggregates.
- In mammals, prions cause fatal neurodegenerative diseases (transmissible spongiform encephalopathies).
- Fungal prions function as heritable, protein-based genetic elements.
Purpose of the Study:
- To investigate prion propagation in the bacterium Escherichia coli.
- To determine the role of the ClpB chaperone in bacterial prion propagation.
Main Methods:
- Utilized the yeast prion protein Sup35 in E. coli.
- Assessed prion propagation under conditions preventing de novo formation.
- Investigated the necessity of ClpB chaperone activity.
Main Results:
- E. coli successfully propagated the Sup35 prion.
- Propagation occurred without de novo prion formation.
- ClpB chaperone disaggregase activity was essential for prion propagation.
Conclusions:
- Bacterial cytoplasm can support prion propagation.
- The ClpB chaperone is crucial for propagating prions in E. coli.
- Suggests potential for protein-based heredity in bacteria.
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