EMD-19522
Structure of the formin INF2 bound to the barbed end of F-actin.
EMD-19522
Single-particle3.41 Å
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Map released: 10/04/2024
Last modified: 24/04/2024
Sample Organism:
Oryctolagus cuniculus,
Homo sapiens
Sample: Complex of the formin INF2 dimer that binds to the actin subunits at the barbed end of actin filaments.
Fitted models: 8rv2 (Avg. Q-score: 0.43)
Deposition Authors: Oosterheert W
,
Boiero Sanders M
,
Funk J
,
Prumbaum D
,
Raunser S
,
Bieling P
Sample: Complex of the formin INF2 dimer that binds to the actin subunits at the barbed end of actin filaments.
Fitted models: 8rv2 (Avg. Q-score: 0.43)
Deposition Authors: Oosterheert W
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Molecular mechanism of actin filament elongation by formins.
Oosterheert W
,
Boiero Sanders M
,
Funk J
,
Prumbaum D
,
Raunser S
,
Bieling P
(2024) Science , 384 , eadn9560 - eadn9560
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(2024) Science , 384 , eadn9560 - eadn9560
Abstract:
Formins control the assembly of actin filaments (F-actin) that drive cell morphogenesis and motility in eukaryotes. However, their molecular interaction with F-actin and their mechanism of action remain unclear. In this work, we present high-resolution cryo-electron microscopy structures of F-actin barbed ends bound by three distinct formins, revealing a common asymmetric formin conformation imposed by the filament. Formation of new intersubunit contacts during actin polymerization sterically displaces formin and triggers its translocation. This "undock-and-lock" mechanism explains how actin-filament growth is coordinated with formin movement. Filament elongation speeds are controlled by the positioning and stability of actin-formin interfaces, which distinguish fast and slow formins. Furthermore, we provide a structure of the actin-formin-profilin ring complex, which resolves how profilin is rapidly released from the barbed end during filament elongation.
Formins control the assembly of actin filaments (F-actin) that drive cell morphogenesis and motility in eukaryotes. However, their molecular interaction with F-actin and their mechanism of action remain unclear. In this work, we present high-resolution cryo-electron microscopy structures of F-actin barbed ends bound by three distinct formins, revealing a common asymmetric formin conformation imposed by the filament. Formation of new intersubunit contacts during actin polymerization sterically displaces formin and triggers its translocation. This "undock-and-lock" mechanism explains how actin-filament growth is coordinated with formin movement. Filament elongation speeds are controlled by the positioning and stability of actin-formin interfaces, which distinguish fast and slow formins. Furthermore, we provide a structure of the actin-formin-profilin ring complex, which resolves how profilin is rapidly released from the barbed end during filament elongation.