Coronin Enhances Actin Filament Severing by Recruiting Cofilin to Filament Sides and Altering F-Actin Conformation

Mouna A. Mikati, Dennis Breitsprecher, Silvia Jansen, Emil Reisler, Bruce L. Goode

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

High rates of actin filament turnover are essential for many biological processes and require the activities of multiple actin-binding proteins working in concert. The mechanistic role of the actin filament severing protein cofilin is now firmly established; however, the contributions of other conserved disassembly-promoting factors including coronin have remained more obscure. Here, we have investigated the mechanism by which yeast coronin (Crn1) enhances F-actin turnover. Using multi-color total internal reflection fluorescence microscopy, we show that Crn1 enhances Cof1-mediated severing by accelerating Cof1 binding to actin filament sides. Further, using biochemical assays to interrogate F-actin conformation, we show that Crn1 alters longitudinal and lateral actin-actin contacts and restricts opening of the nucleotide-binding cleft in actin subunits. Moreover, Crn1 and Cof1 show opposite structural effects on F-actin yet synergize in promoting release of phalloidin from filaments, suggesting that Crn1/Cof1 co-decoration may increase local discontinuities in filament topology to enhance severing.

Original languageEnglish
Pages (from-to)3137-3147
Number of pages11
JournalJournal of Molecular Biology
Volume427
Issue number19
DOIs
StatePublished - Sep 25 2015

Keywords

  • actin
  • cofilin
  • coronin
  • cross-linking
  • severing

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