The glucocorticoid domain of response: measurement of pleiotropic cellular responses by two-dimensional gel electrophoresis.

In this article, we have provided two examples of pleiotropic regulation by specific effector molecules as assayed by two-dimensional gel electrophoresis. In one case, catabolite repression in the bacterium Escherichia coli was examined by measuring the response to cyclic cAMP. In the other, the effect of dexamethasone on the rate of synthesis of over a thousand cell proteins was analyzed in HTC cells. It was found that in E. coli, cAMP regulates the synthesis of about 10 percent of the cell's proteins; both inductions and repressions are observed, but inductions clearly predominate. In HTC cells, dexamethasone induces the synthesis of seven proteins, or about 0.7 percent of the total cellular proteins; repression was not consistently observed. In another rat hepatoma line (FAZA) a similar number but essentially different set of proteins was induced. These data are discussed in terms of the notion of domains of response originally proposed by TOMKINS [1].