Coronin Enhances Actin Filament Severing by Recruiting Cofilin to Filament Sides and Altering F-Actin Conformation.
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.
Mesh Terms:
Actin Cytoskeleton, Actins, Binding Sites, Cofilin 1, Microfilament Proteins, Models, Molecular, Protein Binding, Protein Conformation, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
Actin Cytoskeleton, Actins, Binding Sites, Cofilin 1, Microfilament Proteins, Models, Molecular, Protein Binding, Protein Conformation, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
J. Mol. Biol.
Date: Sep. 25, 2015
PubMed ID: 26299936
View in: Pubmed Google Scholar
Download Curated Data For This Publication
196183
Switch View:
- Interactions 1