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Pertussis toxin and target eukaryotic cells: binding, entry, and activation.
1Department of Physiology, University of Southern California, School of Medicine, Los Angeles 90033.
Summary
Pertussis toxin's S1 subunit disrupts cell signaling via ADP-ribosylation. Its activity requires nucleotide/lipid release and disulfide bond reduction, informing its use as a research tool.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Pertussis toxin is a key virulence factor from Bordetella pertussis.
- It comprises an A protomer (S1 subunit) and a B oligomer.
- The S1 subunit ADP-ribosylates eukaryotic G-proteins, disrupting transmembrane signaling.
Purpose of the Study:
- To elucidate the mechanism of ADP-ribosyltransferase activity of pertussis toxin.
- To identify conditions necessary for S1 subunit activation and function.
- To provide guidance for the use of pertussis toxin as an experimental reagent.
Main Methods:
- Analysis of pertussis toxin structure and function.
- Investigation of the role of nucleotides, membrane lipids, and reductants in toxin activity.
- Modeling of the toxin activation process.
Main Results:
- The B oligomer delivers the S1 subunit to target cells.
- Nucleotides and membrane lipids allosterically facilitate S1 subunit release.
- Reduction of the S1 subunit's disulfide bond by reductants like glutathione is essential for activity.
Conclusions:
- Pertussis toxin activation is a multi-step process involving subunit release and reduction.
- Understanding these steps is crucial for optimizing pertussis toxin's application in research.
- This model provides a framework for the effective use of the toxin as a biochemical tool.