PT - JOURNAL ARTICLE AU - Barrie, Kyle R. AU - Rebowski, Grzegorz AU - Dominguez, Roberto TI - Mechanism of Actin Filament Severing and Capping by Gelsolin AID - 10.1101/2024.09.10.612341 DP - 2024 Jan 01 TA - bioRxiv PG - 2024.09.10.612341 4099 - http://biorxiv.org/content/early/2024/09/10/2024.09.10.612341.short 4100 - http://biorxiv.org/content/early/2024/09/10/2024.09.10.612341.full AB - Gelsolin is the prototypical member of a family of Ca2+-dependent F-actin severing and capping proteins. A structure of Ca2+-bound full-length gelsolin at the barbed end shows domains G1G6 and the inter-domain linkers wrapping around F-actin. Another structure shows domains G1G3, a fragment produced during apoptosis, 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.Competing Interest StatementThe authors have declared no competing interest.