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Updated: Jun 9, 2025

Reconstitution of Actin-Based Motility with Commercially Available Proteins
Published on: October 28, 2022
Mechanism of actin filament severing and capping by gelsolin
Kyle R Barrie1, Grzegorz Rebowski1, Roberto Dominguez2
1Department of Physiology and Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
None:
Gelsolin is the prototypical member of a family of Ca2+-activated F-actin severing and capping proteins. Here we report structures of Ca2+-bound human gelsolin at the barbed end of F-actin. One structure reveals gelsolin's six domains (G1G6) and interdomain linkers wrapping around F-actin, while another shows domains G1G3-a fragment observed during apoptosis-binding on both sides of F-actin. Conformational changes that trigger severing occur on one side of F-actin with G1G6 and on both sides with G1G3. Gelsolin remains bound after severing, blocking subunit exchange.
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