Figure 4.

Gelonin that enters the cell through plasma membrane disruptions abolishes fos protein expression in the injured monolayer. Confluent monolayers of BAE cells were injured as above, except that in addition to the FDx, the protein synthesis inhibitor gelonin was added as well (lower panel). Gelonin is a protein (M_r, ∼40,000 ) that can only exert its effect in cytosol and can only gain access to this domain when a membrane barrier has been breached. Thus, cells in culture that do not experience a PMD are not affected by gelonin, even when it is present at high (mg/ml) concentrations and despite the fact that one gelonin molecule is enough, when present in cytosol, to completely abolish protein synthesis. Controls (upper panel) received dextran only (no gelonin).