title: Stimulation of phosphoinositides breakdown by the heat stable E. coli enterotoxin in rat intestinal epithelial cells.
abstract: Rat intestinal epithelial cells were labelled with [32P]Pi and extracted, and the phospholipids were analysed by thin-layer chromatography. 32P-incorporation in phosphatidylinositol (PI) and phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-phosphate (PIP2) were measured in control and heat stable enterotoxin (ST)-treated cells. ST was found to induce rapid degradation of PIP and PIP2. The degradation of inositol lipids was accompanied by an increase of water soluble inositol phosphate (IP1, IP2, IP3) compounds. There was a two-fold increase of radioactivity in IP2 and IP3 but no significant change was observed in IP1. Phospholipase C activity was increased tenfold with substrate PIP2 in ST-pretreated cells. The present study indicates that ST triggers another second messenger system by increasing the PIP2 hydrolysis with the enzyme phospholipase C.
authors.affiliation: National Institute of Cholera and Enteric Diseases, Calcutta, India.
authors.forename: N
authors.initials: N
authors.lastname: Banik
authors.forename: U
authors.initials: U
authors.lastname: Ganguly
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism*; D002478:Cells, Cultured; D004768:Enterotoxins / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004848:Epithelium / Q000378:metabolism; D029968:Escherichia coli Proteins; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; C034151:heat stable toxin (E coli); D010738:Type C Phospholipases