Diarrheal diseases that are initiated in this way account for around two million deaths annually.[1] For example, cholera is caused by an AB5 protein toxin that has a single toxic A-subunit associated with five nontoxic B-subunits (CTB), which constitute a pentameric receptor for the GM1 glycolipid found on the surface of intestinal epithelial cells.[2] Multivalent binding between CTB and up to five copies of its GM1 ligand facilitates the entry of the toxin into the cell by endocytosis. Here, PCYT1B is linked to diarrheal disease.