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#ADP-ribosylation

2 public questions tagged with this topic.

Pertussis toxin ADP-ribosylates

Pertussis toxin ADP-ribosylates Gαi, preventing the inhibitory G protein from interacting with receptors and thereby blocking its ability to inhibit adenylyl cyclase. The resulting loss of tonic inhibition elevates cAMP levels and contributes to the pathogenesis of whooping cough. The toxin has also become a valuable experimental tool for identifying Gi-coupled pathways.

Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)

Cholera toxin ADP-ribosylates which G-protein subunit?

Cholera toxin catalyzes ADP-ribosylation of Gαs, locking the subunit in its GTP-bound active form by inhibiting GTPase activity. Persistent activation of adenylyl cyclase produces massive elevations of cAMP in intestinal epithelial cells, leading to continuous opening of chloride channels and the characteristic watery diarrhea of cholera. Careful

Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)