Cofilin (ADF) Affects Lateral Contacts in F-actin

Andrey A. Bobkov, Andras Muhlrad, Alexander Shvetsov, Sabrina Benchaar, Damon Scoville, Steven C. Almo, Emil Reisler

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


The effect of yeast cofilin on lateral contacts between protomers of yeast and skeletal muscle actin filaments was examined in solution. These contacts are presumably stabilized by the interactions of loop 262-274 of one protomer with two other protomers on the opposite strand in F-actin. Cofilin inhibited several-fold the rate of interstrand disulfide cross-linking between Cys265 and Cys374 in yeast S265C mutant F-actin, but enhanced excimer formation between pyrene probes attached to these cysteine residues. The possibility that these effects are due to a translocation of the C terminus of actin by cofilin was ruled out by measurements of fluorescence resonance energy transfer (FRET) from tryptophan residues and εATP to acceptor probes at Cys374. Such measurements did not reveal cofilin-induced changes in FRET efficiency, suggesting that changes in Cys265-Cys374 cross-linking and excimer formation stem from the perturbation of loop 262-274 by cofilin. Changes in lateral interactions in F-actin were indicated also by the cofilin-induced partial release of rhodamine phalloidin. Disulfide cross-linking of S265C yeast F-actin inhibited strongly and reversibly the release of rhodamine phalloidin by cofilin. Overall, this study provides solution evidence for the weakening of lateral interactions in F-actin by cofilin.

Original languageEnglish (US)
Pages (from-to)93-104
Number of pages12
JournalJournal of Molecular Biology
Issue number1
StatePublished - Mar 12 2004


  • Actin
  • Cofilin
  • Hydrophobic loop
  • Lateral contacts
  • Phalloidin

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Molecular Biology


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