sentences:  GTP-binding proteins, in particular, are well-established in bAREs pathophysiology.For examples, cholera and heat-labile enterotoxin target the α-subunit of Gs of heterotrimeric GTP-binding proteins.As the α-subunit is ADP-ribosylated, it is permanently in an "active", GTP-bound state; subsequent activation of intracellular cyclic AMP stimulates the release of fluid and ions from intestinal epithelial cells.