key term - Cholera toxin

Definition

Cholera toxin is a protein complex secreted by the bacterium Vibrio cholerae. It disrupts ion transport in the intestines, leading to severe diarrhea.

5 Must Know Facts For Your Next Test

1. Cholera toxin consists of an A subunit and five B subunits.
2. The B subunits bind to GM1 gangliosides on the surface of intestinal epithelial cells.
3. The A subunit enters the cell and activates adenylate cyclase, increasing cAMP levels.
4. Elevated cAMP causes chloride ions to be secreted into the intestinal lumen, followed by water, causing diarrhea.
5. Treatment involves rehydration therapy and antibiotics in severe cases.

Review Questions

Related terms

Vibrio cholerae:

A gram-negative bacterium that causes cholera.

GM1 ganglioside:

A glycosphingolipid found on cell surfaces that serves as a receptor for cholera toxin.

cAMP (cyclic AMP): A secondary messenger important in many biological processes, elevated by cholera toxin activity.