 pertussis toxin, PDX, is a type of bacterial toxin that can cause severe illnesses when it enters human cells. It has two main components, an A subunit, which binds to the G slash O proteins found in humans, and a B subunit, which interacts with cell surface proteins. When the A subunit binds to the G slash O proteins, it causes them to be uncoupled from their normal function, leading to a variety of effects depending on the specific protein. Meanwhile, the B subunit interacts with cell surface proteins, triggering a signal transduction cascade that leads to various cellular responses. This dual mechanism allows PTX to have a wide range of effects on the body. This article was authored by Supachoke Mangmo and Hitoshi Kurose.