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-Structure paper
Title | Direct observation of the conformational states of formin mDia1 at actin filament barbed ends and along the filament. |
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Journal, issue, pages | Mol Biol Cell, Vol. 34, Issue 1, Page ar2, Year 2023 |
Publish date | Jan 1, 2023 |
Authors | Julien Maufront / Bérengère Guichard / Lu-Yan Cao / Aurélie Di Cicco / Antoine Jégou / Guillaume Romet-Lemonne / Aurélie Bertin / |
PubMed Abstract | The fine regulation of actin polymerization is essential to control cell motility and architecture and to perform essential cellular functions. Formins are key regulators of actin filament assembly, ...The fine regulation of actin polymerization is essential to control cell motility and architecture and to perform essential cellular functions. Formins are key regulators of actin filament assembly, known to processively elongate filament barbed ends and increase their polymerization rate. Different models have been extrapolated to describe the molecular mechanism governing the processive motion of formin FH2 domains at polymerizing barbed ends. Using negative stain electron microscopy, we directly identified for the first time two conformations of the mDia1 formin FH2 domains in interaction with the barbed ends of actin filaments. These conformations agree with the speculated open and closed conformations of the "stair-stepping" model. We observed the FH2 dimers to be in the open conformation for 79% of the data, interacting with the two terminal actin subunits of the barbed end while they interact with three actin subunits in the closed conformation. In addition, we identified and characterized the structure of single FH2 dimers encircling the core of actin filaments, and reveal their ability to spontaneously depart from barbed ends. |
External links | Mol Biol Cell / PubMed:36383775 / PubMed Central |
Methods | EM (single particle) |
Resolution | 26.0 - 30.0 Å |
Structure data | EMDB-15947: Direct observation of the open conformational state of formin mDia1 at actin filament barbed end EMDB-15950: Direct observation of the closed conformational state of formin mDia1 at actin filament barbed end EMDB-15957: Direct observation of the conformational state of formin mDia1 dimer along the actin filament |
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