Fig. 7.

The peptide fragment of gelsolin did not induce depolymerization of actin and did not affect actin polymerization. A: time courses for depolymerization of pyrene-F-actin after the addition of 0.1 µM gelsolin peptide fragment (open circle) or full-length gelsolin protein (closed circle). Gelsolin peptide did not cause actin depolymerization assessed as a decrease in pyrene-F-actin fluorescence, whereas full-length gelsolin protein acutely decreased the fluorescence as expected. B: time courses for polymerization of pyrene-F-actin over a period of 1 h. Buffer control (closed triangle) and gelsolin peptide (open circle) samples resulted in similar fluorescence intensity. Full-length gelsolin protein (closed circle) increased fluorescence initially but subsequently reached lower fluorescence plateau, consistent with gelsolin’s actin filament capping effect. Latrunculin A (open inverted triangle) served as a control for the prevention of polymerization. The data shown are representative of 3 experiments for both depolymerization and polymerization.