Two opposite effects of cofilin on the thermal unfolding of F-actin

a differential scanning calorimetric study

Irina V. Dedova, Olga P. Nikolaeva, Valeria V. Mikhailova, Cris G. dos Remedios, Dmitrii I. Levitsky*

*Corresponding author for this work

Research output: Contribution to journalArticle

38 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)119-128
Number of pages10
JournalBiophysical Chemistry
Issue number1-2
Publication statusPublished - 1 Jul 2004
Externally publishedYes


  • Actin
  • ADF, actin depolymerizing factor
  • Cofilin
  • Differential scanning calorimetry
  • DSC, differential scanning calorimetry.
  • Thermal unfolding

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