Open AccessRate constant for capping of the barbed ends of actin filaments by the gelsolin‐actin complex
Author(s) -
SELVE Norma,
WEGNER Albrecht
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb09504.x
Subject(s) - gelsolin , actin , mdia1 , treadmilling , actin remodeling , filamin , actin binding protein , chemistry , microfilament , protein filament , biophysics , actina , actin cytoskeleton , biology , cytoskeleton , biochemistry , cell
The rate of capping of actin filaments by the gelsolin‐actin complex was measured by inhibition of elongation of the barbed ends of actin filaments. Polymeric actin (0.1 – 1.0 μM) was added to 0.5 μM monomeric actin and various concentrations of the gelsolin‐actin complex (0.08–2.4 nM) to induce nucleated polymerization. As under the experimental conditions (2 mM MgCl 2 , 100 mM KCl, 37°C, actin monomer concentration ≤ 0.5 μM) actin filaments treadmilled, filaments elongated only at the barbed ends and the gelsolin‐actin complex did not nucleate actin filaments to polymerize towards the pointed ends. The rate of nucleated actin polymerization in the presence of the gelsolin‐actin complex was quantitatively analyzed. The rate constant for capping of the barbed ends of actin filaments by the gelsolin‐actin complex was found to be about 10 7 M −1 s −1 .