EMD-19522

Single-particle
3.41 Å
EMD-19522 Deposition: 31/01/2024
Map released: 10/04/2024
Last modified: 24/04/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-19522

Structure of the formin INF2 bound to the barbed end of F-actin.

EMD-19522

Single-particle
3.41 Å
EMD-19522 Deposition: 31/01/2024
Map released: 10/04/2024
Last modified: 24/04/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
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
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
PUBMED: 38603491
DOI: doi:10.1126/science.adn9560
ISSN: 1095-9203
ASTM: SCIEAS
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.