Editing Exotoxin (section)

==== By mechanism ====

Once in the cell, many of the exotoxins act at the eukaryotic [[ribosome]]s (especially [[60S]]), as [[protein synthesis inhibitor]]s. (Ribosome structure is one of the most important differences between eukaryotes and prokaryotes, and, in a sense, these exotoxins are the bacterial equivalent of antibiotics such as [[clindamycin]].)

* Some exotoxins act directly at the ribosome to inhibit protein synthesis. An example is [[Shiga toxin]].
* Other toxins act at [[elongation factor-2]]. In the case of the [[diphtheria toxin]], EF2 is ADP-ribosylated and becomes unable to participate in protein elongation, and, so, the cell dies. [[Pseudomonas exotoxin]] has a similar action.

Other intracellular toxins do not directly inhibit protein synthesis.
* For example, [[Cholera toxin]] ADP-ribosylates, thereby activating tissue adenylate cyclase to increase the concentration of cAMP, which causes the movement of massive amounts of fluid and electrolytes from the lining of the small intestine and results in life-threatening diarrhea.
* Another example is [[Pertussis toxin]].