oxhamre

The toxin alpha-hemolysin expressed by uropathogenic Escherichia coli bacteria was recently shown as the first pathophysiologically relevant protein to induce oscillations of the intracellular Ca(2+) concentration in target cells. Here, we propose a generic three-variable kinetic model describing the Ca(2+) oscillations induced in single rat renal epithelial cells by this toxin. Specifically, we take into account the interplay between 1), the cytosolic Ca(2+) concentration; 2), IP(3)-sensitive Ca(2+) channels located in the membrane separating the cytosol and endoplasmic reticulum; and 3), toxin-related activation of production of IP(3) by phospholipase C. With these ingredients, the predicted response of cells exposed to the toxin is in good agreement with the results of experiments.