Vibrio cholerae: cholera toxin.
The bacterial protein toxin of Vibrio cholerae, cholera toxin, is a major agent involved in severe diarrhoeal disease. Cholera toxin is a member of the AB toxin family and is composed of a catalytically active heterodimeric A-subunit linked with a homopentameric B-subunit. Upon binding to its receptor, GM0(1), cholera toxin is internalized and transported in a retrograde manner through the Golgi to the ER, where it is retrotranslocated to the cytosol. Here, cholera toxin reaches its intracellular target, the basolaterally located adenylate cyclase which becomes constitutively activated after toxin-induced mono-ADP-ribosylation of the regulating G(S)-protein. Elevated intracellular cAMP levels provoke loss of water and electrolytes which is manifested as the typical diarrhoea. The cholera toxin B-subunit displays the capacity to fortify immune responses to certain antigens, to act as a carrier and to be competent in inducing immunological tolerance. These unique features make cholera toxin a promising tool for immunologists.
Vanden Broeck
Davy
D
UA-Laboratory of Human Biochemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium. davy.vandenbroeck@ua.ac.be
Horvath
Caroline
C
De Wolf
Marc J S
MJ
D002771:Cholera / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D008958:Models, Molecular; D014734:Vibrio cholerae / Q000472:pathogenicity* / Q000502:physiology; D037521:Virulence Factors / Q000737:chemistry / Q000502:physiology
D037521:Virulence Factors; D002772:Cholera Toxin