INTERACTIONS OF ELONGATION-FACTOR-2 WITH THE CYTOSKELETON AND INTERFERENCE WITH DNASE-I BINDING TO ACTIN

Interactions of elongation factor 2 (EF-2) with G-actin and F-actin in vitro were investigated using viscosimetry, gel filtration and electr on microscopy. Under depolymerization conditions, at a molar ratio of 0.5:1 (EF-2/F-actin subunit), F-actin is stabilised by EF-2 and filame nts depolymerize about three times slower than control solutions conta ining only F-actin. Filament stability is improved also when EF-2 is i ncluded in the solution in the presence of DNase I. Electron micrograp hs and viscosity measurements indicate that EF-2 may support small bun dles with a width of 2 or 3 filaments. It was established that EF-2 in teracts with G-actin in vitro, and reduces G-actin inhibition of DNase I activity when it is present at a ratio of 1:1. Results are discusse d in the context of possible functional significance of the interactio ns.