Two opposite effects of cofilin on the thermal unfolding of F-actin: a differential scanning calorimetric study
- 作者：Dedova ; Irina V. ; Nikolaeva ; Olga P. ; Mikhailova ; Valeria V. ; dos Remedios ; Cris G. ; Levitsky ; Dmitrii I.
- 关键词：Cofilin ; Actin ; Thermal unfolding ; Differential scanning calorimetry ; ADF ; actin depolymerizing factor ; DSC ; differential scanning calorimetry.
- 刊名：Biophysical Chemistry
- 出版年：2004
- 期刊代码：11_03014622
- 类别：ch
- 出版时间：July 1, 2004
- 卷：110
- 期：1-2
- 页码：119-128
- 文件大小：535 K
摘要
Differential scanning calorimetry was used to examine the effects of cofilin on the thermal unfolding of actin. Stoichiometric binding increases the thermal stability of both G- and F-actin but at sub-saturating concentrations cofilin destabilizes F-actin. At actin:cofilin molar ratios of 1.5–6 the peaks corresponding to stabilized (66–67 °C) and destabilized (56–57 °C) F-actin are observed simultaneously in the same thermogram. Destabilizing effects of sub-saturating cofilin are highly cooperative and are observed at actin:cofilin molar ratios as low as 100:1. These effects are abolished by the addition of phalloidin or aluminum fluoride. Conversely, at saturating concentrations, cofilin prevents the stabilizing effects of phalloidin and aluminum fluoride on the F-actin thermal unfolding. These results suggest that cofilin stabilizes those actin subunits to which it directly binds, but destabilizes F-actin with a high cooperativity in neighboring cofilin-free regions.