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Updated: May 27, 2026

Detection of Toxin Translocation into the Host Cytosol by Surface Plasmon Resonance
Published on: January 3, 2012
G(i/o) protein-dependent and -independent actions of Pertussis Toxin (PTX)
Supachoke Mangmool1, Hitoshi Kurose
1Department of Pharmacology, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya, Rajathevi, Bangkok, Thailand. pysmm@mahidol.ac.th
Abstract:
Pertussis toxin (PTX) is a typical A-B toxin. The A-protomer (S1 subunit) exhibits ADP-ribosyltransferase activity. The B-oligomer consists of four subunits (S2 to S5) and binds extracellular molecules that allow the toxin to enter the cells. The A-protomer ADP-ribosylates the α subunits of heterotrimeric G(i/o) proteins, resulting in the receptors being uncoupled from the G(i/o) proteins. The B-oligomer binds proteins expressed on the cell surface, such as Toll-like receptor 4, and activates an intracellular signal transduction cascade. Thus, PTX modifies cellular responses by at least two different signaling pathways; ADP-ribosylation of the Gα(i/o) proteins by the A-protomer (G(i/o) protein-dependent action) and the interaction of the B-oligomer with cell surface proteins (G(i/o) protein-independent action).
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