TY - JOUR
T1 - Structural Basis for Actin Assembly, Activation of ATP Hydrolysis, and Delayed Phosphate Release
AU - Murakami, Kenji
AU - Yasunaga, Takuo
AU - Noguchi, Taro Q.P.
AU - Gomibuchi, Yuki
AU - Ngo, Kien X.
AU - Uyeda, Taro Q.P.
AU - Wakabayashi, Takeyuki
N1 - Funding Information:
We thank Dr. Murray Stewart (MRC Lab. Mol. Biol., Cambridge) for discussions and advice on crystallography; Dr. Ralph Davis and Dr. Karl-Magnus Larsson (Stanford University) for critical reading of the manuscript; Dr. Akihiro Narita for his contribution to this work at the early stages; Dr. Soichi Wakatsuki and colleagues at Photon Factory, KEK for data collection at the synchrotron site; Dr. Koji Yonekura for the program to calculate a figure of merit; Dr. Hideo Higuchi for fluorometry; and Yuji Tuji, Akito Tominaga, Ryuta Mikawa, and Harumi Kiuchi for assistance with crystallography and/or biochemical experiments. This work was supported by grants from Human Frontier Science Program and Grant-in-Aid for Scientific Research on Priority Areas (Bio-supramolecule) from the Ministry of Education, Science, Technology, and Sports of Japan to T.W. and a grant from SENTAN, JST to T.Q.P.U.
PY - 2010/10/15
Y1 - 2010/10/15
N2 - Assembled actin filaments support cellular signaling, intracellular trafficking, and cytokinesis. ATP hydrolysis triggered by actin assembly provides the structural cues for filament turnover in vivo. Here, we present the cryo-electron microscopic (cryo-EM) structure of filamentous actin (F-actin) in the presence of phosphate, with the visualization of some α-helical backbones and large side chains. A complete atomic model based on the EM map identified intermolecular interactions mediated by bound magnesium and phosphate ions. Comparison of the F-actin model with G-actin monomer crystal structures reveals a critical role for bending of the conserved proline-rich loop in triggering phosphate release following ATP hydrolysis. Crystal structures of G-actin show that mutations in this loop trap the catalytic site in two intermediate states of the ATPase cycle. The combined structural information allows us to propose a detailed molecular mechanism for the biochemical events, including actin polymerization and ATPase activation, critical for actin filament dynamics.
AB - Assembled actin filaments support cellular signaling, intracellular trafficking, and cytokinesis. ATP hydrolysis triggered by actin assembly provides the structural cues for filament turnover in vivo. Here, we present the cryo-electron microscopic (cryo-EM) structure of filamentous actin (F-actin) in the presence of phosphate, with the visualization of some α-helical backbones and large side chains. A complete atomic model based on the EM map identified intermolecular interactions mediated by bound magnesium and phosphate ions. Comparison of the F-actin model with G-actin monomer crystal structures reveals a critical role for bending of the conserved proline-rich loop in triggering phosphate release following ATP hydrolysis. Crystal structures of G-actin show that mutations in this loop trap the catalytic site in two intermediate states of the ATPase cycle. The combined structural information allows us to propose a detailed molecular mechanism for the biochemical events, including actin polymerization and ATPase activation, critical for actin filament dynamics.
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U2 - 10.1016/j.cell.2010.09.034
DO - 10.1016/j.cell.2010.09.034
M3 - Article
C2 - 20946985
AN - SCOPUS:77957793677
SN - 0092-8674
VL - 143
SP - 275
EP - 287
JO - Cell
JF - Cell
IS - 2
ER -