Single Actin Bundle Rheology

Strehle, Dan; Mollenkopf, Paul; Gläser, Martin; Golde, Tom; Schuldt, Carsten; Käs, Josef A.; Schnauß, Jörg

doi:10.3390/molecules22101804

Cited by 15 publications

(18 citation statements)

References 45 publications

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“…In addition to the apparent visual differences, the fluctuations of the formed bundles decreased with increasing sPX concentration as a direct result of their thicker, more tightly packed structure. [30,32]…”

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confidence: 99%

Synthetic Transient Crosslinks Program the Mechanics of Soft, Biopolymer‐Based Materials

et al. 2018

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Actin networks are adaptive materials enabling dynamic and static functions of living cells. A central element for tuning their underlying structural and mechanical properties is the ability to reversibly connect, i.e., transiently crosslink, filaments within the networks. Natural crosslinkers, however, vary across many parameters. Therefore, systematically studying the impact of their fundamental properties like size and binding strength is unfeasible since their structural parameters cannot be independently tuned. Herein, this problem is circumvented by employing a modular strategy to construct purely synthetic actin crosslinkers from DNA and peptides. These crosslinkers mimic both intuitive and noncanonical mechanical properties of their natural counterparts. By isolating binding affinity as the primary control parameter, effects on structural and dynamic behaviors of actin networks are characterized. A concentration-dependent triphasic behavior arises from both strong and weak crosslinkers due to emergent structural polymorphism. Beyond a certain threshold, strong binding leads to a nonmonotonic elastic pulse, which is a consequence of self-destruction of the mechanical structure of the underlying network. The modular design also facilitates an orthogonal regulatory mechanism based on enzymatic cleaving. This approach can be used to guide the rational design of further biomimetic components for programmable modulation of the properties of biomaterials and cells.

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confidence: 99%

Synthetic Transient Crosslinks Program the Mechanics of Soft, Biopolymer‐Based Materials

et al. 2018

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“…OT have been used to measure the bending stiffness of microtubules ( Kurachi et al, 1995 ; Felgner et al, 1996 ; van Mameren et al, 2009 ; Koch and Rohrbach, 2018 ; Memet et al, 2018 ), actin filaments ( van Mameren et al, 2009 ) and collagen fibrils ( Dutov et al, 2016 ). Other examples of mechanical properties of protein fibers measured with OT include torsional stiffness ( Tsuda et al, 1996 ; Yasuda et al, 1996 ), bending stiffness of fiber bundles ( Rückerl et al, 2017 ; Strehle et al, 2017 ), sliding forces of filaments within bundles ( Schnauß et al, 2016 ), and bending and spontaneous assembly of two interacting filaments using a four-trap OT instrument ( Kurniawan Nicholas et al, 2016 ). OT can also be used to measure the assembly and disassembly of individual protein filaments, as has been done for microtubules ( Dogterom et al, 2005 ; Rodríguez-García et al, 2020 ).…”

Section: Mechanics Of Higher-order Protein Fibers and Networkmentioning

confidence: 99%

Optical Tweezers Approaches for Probing Multiscale Protein Mechanics and Assembly

Lehmann

Shayegan

Blab

et al. 2020

Front. Mol. Biosci.

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Multi-step assembly of individual protein building blocks is key to the formation of essential higher-order structures inside and outside of cells. Optical tweezers is a technique well suited to investigate the mechanics and dynamics of these structures at a variety of size scales. In this mini-review, we highlight experiments that have used optical tweezers to investigate protein assembly and mechanics, with a focus on the extracellular matrix protein collagen. These examples demonstrate how optical tweezers can be used to study mechanics across length scales, ranging from the single-molecule level to fibrils to protein networks. We discuss challenges in experimental design and interpretation, opportunities for integration with other experimental modalities, and applications of optical tweezers to current questions in protein mechanics and assembly.

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“…Data points in all curves represent the mean of at least five independent measurements and error bars represent the standard deviation from the mean. To date, previous in vitro studies have investigated the mechanical properties of only one-component systems of either actin as entangled [33][34][35] and crosslinked [36][37][38][39][40] networks or keratin networks 24,25,30,31,41 and single filaments. 42 In our study, , composite networks of F-actin and K8-K18 with varying mixing ratios revealed an intermediate linear viscoelastic behavior with regard to their composite-specific protein content.…”

Section: Figmentioning

confidence: 99%

Keratins determine network stress responsiveness in reconstituted actin-keratin filament systems

Elbalasy

Mollenkopf

Tutmarc

et al. 2020

Preprint

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The cytoskeleton is a major determinant of cell mechanics, a property that is altered during many pathological situations. To understand these alterations, it is essential to investigate the interplay between the main filament systems of the cytoskeleton in the form of composite networks. Here, we investigate the role of keratin intermediate filaments (IFs) in network strength by studying in vitro reconstituted actin and keratin 8/18 composite networks via bulk shear rheology. We co-polymerized these structural proteins in varying ratios and recorded how their relative content affects the overall mechanical response of the various composites. For relatively small deformations, we found that all composites exhibited an intermediate linear viscoelastic behavior compared to that of the pure networks. In stark contrast, the composites displayed increasing strain stiffening behavior as a result of increased keratin content when larger deformations were imposed. This strain stiffening behavior is fundamentally different from behavior encountered with vimentin IF as a composite network partner for actin. Our results provide new insights into the mechanical interplay between actin and keratin in which keratin provides reinforcement to actin. This interplay may contribute to the overall integrity of cells, providing an explanation for the stability of stressed epithelial tissues due to their high keratin contents. Additionally, this helps us to understand the physiological necessity to exchange IF systems during epithelial-mesenchymal transition (EMT) in order to suppress strain stiffening of the network, making cells more elastic and, thus, facilitating their migration through dense tissues.

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Single Actin Bundle Rheology

Cited by 15 publications

References 45 publications

Synthetic Transient Crosslinks Program the Mechanics of Soft, Biopolymer‐Based Materials

Synthetic Transient Crosslinks Program the Mechanics of Soft, Biopolymer‐Based Materials

Optical Tweezers Approaches for Probing Multiscale Protein Mechanics and Assembly

Keratins determine network stress responsiveness in reconstituted actin-keratin filament systems

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