Lateral Subunit Coupling Determines Intermediate Filament Mechanics

Lorenz, Charlotta; Forsting, Johanna; Schepers, Anna V.; Kraxner, Julia; Bauch, Susanne; Witt, Hannes; Klumpp, Stefan; Koester, Sarah

doi:10.1101/676197

Cited by 5 publications

(10 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Metastable filaments were weighted according to the total number of stable and metastable curves and projected onto the average curve up to their yield-strain. 34 Analysis of the slope of the plateaus: The plateau of each single force-strain curve was analyzed for all stable filaments as they show a complete plateau. A typical analysis for one single force-strain curve is shown in Supplementary Fig.…”

Section: Discussionmentioning

confidence: 99%

“…4b, that describes the size of fully coupled lateral subunits into which the monomers are organized. 34 Thus, in higher order subunits, more elements have to unfold simultaneously to achieve the length change, ∆L, of the filament. This effect already plays a role for the initial stretching and leads to a slightly increased slope (see inset of Fig.…”

Section: If Stiffening Saturates At Low Phmentioning

confidence: 99%

“…A vimentin filament was mechanically modeled as previously described. 12,34 The forcestrain behavior of the modeled filament was determined by a Monte-Carlo simulation written in MatLab. 34 The simulation was run with one varied parameter while keeping the others constant as shown in Fig.…”

Section: Force-strain Monte-carlo Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Tuning Intermediate Filament Mechanics by Variation of pH and Ion Charges

Schepers

Lorenz

Köster

2019

Preprint

Self Cite

View full text Add to dashboard Cite

8The cytoskeleton is formed by three types of filamentous proteins -microtubules, actin fila-9 ments, and intermediate filaments (IFs) -and enables cells to withstand external and internal 10 forces. Vimentin is the most abundant IF in humans and has remarkable mechanical properties, 11 such as high extensibility and stability. It is, however, unclear to which extent these properties 12 are influenced by the electrostatic environment. Here, we study the mechanical properties of 13 single vimentin filaments by employing optical trapping combined with microfluidics. Force-14 strain curves, recorded at varying ion concentrations and pH values, reveal that the mechanical 15 properties of single vimentin IFs are influenced by direct (pH) and indirect (ionic) charge vari-16 ations. By combination with Monte Carlo simulations, we connect these altered mechanics to 17 electrostatic interactions of subunits within the filaments. We thus find possible mechanisms 18 that allow cells to locally tune their stiffness without remodelling the entire cytoskeleton. 19One-Sentence-Summary: Adaptable force-strain behaviour of single cytoskeletal filaments 20 in varying electostatic conditions allow cells to tune their mechanical properties rapidly and 21 locally. 22 1 MAIN TEXT 23 Introduction 24It is meanwhile well accepted that the mechanical properties of cells are, to a large extent, 25 governed by the cytoskeleton, a stabilising, yet flexible framework, which is composed of mi-26 crotubules, actin filaments, and intermediate filaments (IFs), together with motor proteins and 27 crosslinkers. While microtubules and actin filaments are conserved in eukaryotic cell types, 28 there are around 70 different genes encoding IFs in man that are expressed according to the 29 cell's specific requirements (1, 2). 30Despite differences in their amino acid sequence, all cytoskeletal IF proteins share their sec-31 ondary structure with a tripartite alpha-helical rod and disordered head and tail domains (3, 4). 32During the hierarchical assembly, two monomers form a parallel coiled coil and these dimers 33 organise into anti-parallel tetramers in a half-staggered arrangement. The tetramers assemble 34 laterally to form unit length filaments (ULFs), which in turn elongate to filaments by end-to-end 35 annealing (3). The resulting biopolymer comprises a complex high-order arrangement of coiled 36 coils (3), which allows IFs to be extended up to at least 4.5-fold their initial length (5-7). This 37 enormous extensibility is in stark contrast to microtubules and F-actin (8). 38Vimentin is the IF typically expressed in mesenchymal cells (2) and up-regulated during the 39 epithelial-to-mesenchymal transition in wound healing, early embryogenesis, and cancer meta-40 stasis (9). In addition to being highly extensible (7, 10, 11) vimentin is flexible (12-14) and 41 stable (15). During stretching, three regimes are observed in the force-strain data (7, 10, 11, 16, 42 17): an initial linear, elastic increase, a plateau of relatively constant force...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: If Stiffening Saturates At Low Phmentioning

confidence: 99%

See 1 more Smart Citation

Tuning Intermediate Filament Mechanics by Variation of pH and Ion Charges

Schepers

Lorenz

Köster

2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…5 This hierarchical structure of IFs, in contrast to polar microtubules or actin filaments, grants IFs their unique mechanical properties. [6][7][8] The most abundant IF protein, vimentin, is found in cells of mesenchymal origin. 5,9 Single vimentin filaments are highly extensible and can be elongated up to at least 4.5 fold.…”

mentioning

confidence: 99%

“…5 This hierarchical structure of IFs, in contrast to polar microtubules or actin filaments, grants IFs their unique mechanical properties. 6–8…”

mentioning

confidence: 99%

Post-Translational Modifications Soften Vimentin Intermediate Filaments

Kraxner

Lorenz

Menzel

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

The mechanical properties of biological cells are determined by the cytoskeleton, a composite biopolymer network consisting of microtubules, actin filaments and intermediate filaments (IFs). By differential expression of the cytoskeletal proteins, modulation of the network architecture and the interactions between the filaments, cell mechanics may be adapted to varying requirements on the cell. Here, we focus on the intermediate filament protein vimentin and introduce post-translational modifications as an additional, much faster mechanism for mechanical modulation. We study the impact of phosphorylation on filament mechanics by recording precise force-strain curves using optical traps. Whereas full phosphorylation leads to disassembly of IFs, partial phosphorylation results in softening of the filaments. We show that binding of the protein 14-3-3 to phosphorylated vimentin IFs further enhances this effect and speculate that in the cell 14-3-3 may serve to preserve the softening and thereby the altered cell mechanics. By employing phosphomimetic mutants and complementary Monte Carlo simulations, we explain our observation through the additional charges introduced during.The cytoskeleton of eukaryotes consists of three filament systems -microtubules, actin filaments and intermediate filaments (IFs) -which form a complex biopolymer network. The exact composition of the cytoskeleton and the interplay between the three filament types are of great importance as they define the mechanical properties of different cell types. 1Microtubules and actin filaments are highly conserved throughout cell types and between organisms, whereas more than 70 human genes encode for IFs. 2 Although different IFs are expressed in a cell type specific manner, they all share the same hierarchical assembly pathway from monomers to filaments. The secondary structure of the monomers consists of an α-helical rod domain, flanked by intrinsically disordered head and tail domains. 3,4 During assembly, two monomers align and form parallel coiled-coil dimers, two dimers form antiparallel, half-staggered tetramers, and multiple tetramers constitute a unit-length filament (ULF) (see Fig. 1a). Subsequent longitudinal annealing yields elongated filaments with a diameter of about 10 nm. 5 This hierarchical structure of IFs, in contrast to polar microtubules or actin filaments that elongate by rapid growth at the plus-end, grants IFs their unique mechanical properties. [6][7][8] Here, we study the most abundant IF, vimentin, which is found in cells of mesenchymal origin. 5,9 Single vimentin filaments are highly extensible and can be elongated up to at least 4.5 fold. 7,10,11 During elongation, three regimes are observed in the force-strain curves: an initial linear (elastic) increase, a plateau region and a subsequent stiffening. 6,7,12,13 These

show abstract

Advances in mechanical biomarkers

Eroles

Rico

2023

J of Molecular Recognition

View full text Add to dashboard Cite

Mechanical biomarkers distinguish health conditions through quantitative mechanical measurements. The emergence and establishment of nanotechnology in the last decades have provided new tools to obtain mechanical biomarkers at the nanoscale.Mechanical measurements are reproducible, label-free, start to be applied in vivo can be high throughput, and require small samples. Mechanical protocols in clinical practice at the macro scale like palpation or blood pressure measurement are routinely used by medical doctors. Nanotechnology brought mechanical sensing to the next scale, where cells, tissues, and proteins can be probed and linked to medical conditions. Mechanical changes in cells and tissues may be detected before other markers, such as protein expression, providing an important advantage as biomarkers. In the present review, we explore the biomarker's historical evolution, describe mechanical biomarkers on various diseases and novel discoveries in the nanomechanical field for their characterization. We conclude that mechanical biomarkers are establishing novel hallmarks in diseases, in several cases for early diagnostics of diseases and discovery of drug targets in the proteins involved in the mechanical changes, while advances in instrumentation are bringing commercial products into the clinical practice. Mechanical biomarkers along with clinical testing are establishing an important niche in the market, whose demand is increasing due to the expansion of personalized medicine and unmet needs in the clinics.

show abstract

Lateral Subunit Coupling Determines Intermediate Filament Mechanics

Cited by 5 publications

References 45 publications

Tuning Intermediate Filament Mechanics by Variation of pH and Ion Charges

Tuning Intermediate Filament Mechanics by Variation of pH and Ion Charges

Post-Translational Modifications Soften Vimentin Intermediate Filaments

Advances in mechanical biomarkers

Contact Info

Product

Resources

About