Final answer:
The pertussis toxin acts on the Gi protein.
Step-by-step explanation:
Pertussis toxin is an exotoxin produced by the bacterium Bordetella pertussis, which causes whooping cough or pertussis in humans. The toxin plays a crucial role in the pathogenesis of the disease by interfering with the host's cellular signaling, particularly by modifying the function of certain G proteins.
The pertussis toxin acts on the Gi protein. The toxin, produced by the bacteria Bordetella pertussis, specifically targets the Gi protein, a type of G protein involved in signal transduction.