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 - Funding Information:
We are grateful to Dr. M. Gandhi and F. Chaudhry for providing some of the proteins used in TIRF experiments and to Dr. M. L. Phillips (University of California, Los Angeles) for assistance with EM. We thank Dr. Durer (University of California, Los Angeles) for the EM image showing the products of polymerization of cross-linked C50/C265 actin in the presence of Cof1 ( Fig. 5 e). This work was supported by grants from National Institutes of Health to E.R. ( GM077190 ) and B.G. ( GM063691 ).
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 -