Immunological probes into the mechanism of cholera toxin action

The use of antibodies to specific cell surface proteins or to ligands which interact with cell surface receptors is a powerful tool for analyzing the properties of membrane proteins and the consequences of specific cell surface ligand-receptor interactions. Two central observations concerning membrane structure and function, - the diffusibility of membrane proteins (1) and ligand-triggered modulation of specific receptors (2), have derived from the use of antibodies to analyze the properties of membrane proteins. In our study of the mechanism of action of cholera toxin, a protein which binds to a specific cell surface receptor and results in the activation of adenyl cyclase, considerable information has been gained through the use of immunological techniques. This review will briefly summarize the data underlying our current concept of cholera toxin action at the cell membrane and will emphasize those observations made through the use of immunological approaches.