Cholera Toxin

**Semantic type:** Amino Acid, Peptide, or Protein|Hazardous or Poisonous Substance

**Definition:** Secreted by Vibrio cholerae, Cholera Toxin is a natural bacterial enterotoxin consisting of major components heavy A- and light B peptides (choleragenoid) that initiates a signaling cascade in intestinal epithelial cells causing a dysfunction of chloride channels, loss of water, and diarrhea. B peptide anchors the protein to epithelia; A peptide enters the cytoplasm and activates adenylate cyclase. Due to its cytotoxicity, cholera toxin is being studied for tumor cell targeting and cancer chemotherapy. (NCI04)