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Toxins (Basel). 2011 Jul;3(7):884-99. doi: 10.3390/toxins3070884. Epub 2011 Jul 15.

G(i/o) protein-dependent and -independent actions of Pertussis Toxin (PTX).

Author information

1
Department 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).

KEYWORDS:

A-protomer; ADP-ribosylation; B-oligomer; G protein-coupled receptor; Gi/o-dependent; Gi/o-independent; Toll-like receptor 4; heterotrimeric G protein; pertussis toxin

PMID:
22069745
PMCID:
PMC3202852
DOI:
10.3390/toxins3070884
[Indexed for MEDLINE]
Free PMC Article

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