TY - JOUR
T1 - Coronin Enhances Actin Filament Severing by Recruiting Cofilin to Filament Sides and Altering F-Actin Conformation
AU - Mikati, Mouna A.
AU - Breitsprecher, Dennis
AU - Jansen, Silvia
AU - Reisler, Emil
AU - Goode, Bruce L.
N1 - Publisher Copyright:
© 2015 The Authors. Published by Elsevier Ltd.
PY - 2015/9/25
Y1 - 2015/9/25
N2 - 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.
AB - 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.
KW - actin
KW - cofilin
KW - coronin
KW - cross-linking
KW - severing
UR - http://www.scopus.com/inward/record.url?scp=84941935104&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2015.08.011
DO - 10.1016/j.jmb.2015.08.011
M3 - Article
C2 - 26299936
AN - SCOPUS:84941935104
SN - 0022-2836
VL - 427
SP - 3137
EP - 3147
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 19
ER -