Plastic Deformation and Fragmentation of Strained Actin Filaments

Anthony C. Schramm, Glen Hocky, Gregory A. Voth, Jean Louis Martiel, Enrique M. De La Cruz

Research output: Contribution to journalArticle

Abstract

The assembly of actin filaments and filament networks generate forces that drive cell and vesicle movement. These structures and the comprising actin filaments must be mechanically stable to sustain these forces and maintain their structural integrity. Filaments in these dynamic structures must also be disassembled to recycle and replenish the pool of actin monomers available for polymerization. Actin-severing proteins such as cofilin and contractile myosin motor proteins fragment these nominally stable structures. We developed a mesoscopic-length-scale actin filament model to investigate force-induced filament fragmentation. We show that fragmentation in our model occurs at curvatures similar to previous measurements of fragmentation within (cofil)actin and actin-cofilactin boundaries. Boundaries between bare and cofilin-decorated segments are brittle and fragment at small bending and twisting deformations. Extending filaments disperses strain uniformly over subunit interfaces, and filaments fragment with no detectable partial rupture or plastic deformation. In contrast, bending or twisting filaments imposes nonuniform interface strain and leads to partial interface rupture, accelerating filament fragmentation. As a result, the rupture force under compressive loads is an order of magnitude lower than under tensile loads. Partial interface rupture may be a primary mechanism of accelerating actin filament fragmentation by other actin-destabilizing proteins.

Original languageEnglish (US)
JournalBiophysical journal
DOIs
StatePublished - Jan 1 2019

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Actin Cytoskeleton
Plastics
Actins
Rupture
Actin Depolymerizing Factors
Proteins
Myosins
Polymerization
Cell Movement

ASJC Scopus subject areas

  • Biophysics

Cite this

Plastic Deformation and Fragmentation of Strained Actin Filaments. / Schramm, Anthony C.; Hocky, Glen; Voth, Gregory A.; Martiel, Jean Louis; De La Cruz, Enrique M.

In: Biophysical journal, 01.01.2019.

Research output: Contribution to journalArticle

Schramm, Anthony C. ; Hocky, Glen ; Voth, Gregory A. ; Martiel, Jean Louis ; De La Cruz, Enrique M. / Plastic Deformation and Fragmentation of Strained Actin Filaments. In: Biophysical journal. 2019.
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