scholarly journals Extracting the dynamic correlation length of actin networks from microrheology experiments

Soft Matter ◽  
2014 ◽  
Vol 10 (41) ◽  
pp. 8324-8329 ◽  
Author(s):  
Adar Sonn-Segev ◽  
Anne Bernheim-Groswasser ◽  
Yael Roichman
Keyword(s):  
Correlation Length ◽  
Actin Filament ◽  
Mechanical Response ◽  
Length Scale ◽  
Filament Length ◽  
Actin Networks ◽  
Dynamic Correlation

Microrheology is used to measure the length scale dependent mechanical response of F-actin gels. The dynamic correlation length thus measured has a non-trivial dependence on the actin filament length.

scholarly journals Actin Filament Length Tunes Elasticity of Flexibly Cross-Linked Actin Networks

2010 ◽  
Vol 99 (4) ◽  
pp. 1091-1100 ◽  
Author(s):  
K.E. Kasza ◽  
C.P. Broedersz ◽  
G.H. Koenderink ◽  
Y.C. Lin ◽  
W. Messner ◽  
...  
Keyword(s):  
Actin Filament ◽  
Filament Length ◽  
Actin Networks

scholarly journals Tropomyosin isoforms differentially tune actin filament length and disassembly

2019 ◽  
Vol 30 (5) ◽  
pp. 671-679 ◽  
Author(s):  
Silvia Jansen ◽  
Bruce L. Goode
Keyword(s):  
Fluorescence Microscopy ◽  
Actin Filament ◽  
Actin Filaments ◽  
Total Internal Reflection ◽  
Internal Reflection ◽  
Total Internal Reflection Fluorescence ◽  
Filament Length ◽  
Actin Networks ◽  
Tropomyosin Isoforms ◽  
Specific Effects

Cellular actin networks exhibit diverse filamentous architectures and turnover dynamics, but how these differences are specified remains poorly understood. Here, we used multicolor total internal reflection fluorescence microscopy to ask how decoration of actin filaments by five biologically prominent Tropomyosin (TPM) isoforms influences disassembly induced by Cofilin alone, or by the collaborative effects of Cofilin, Coronin, and AIP1 (CCA). TPM decoration restricted Cofilin binding to pointed ends, while not interfering with Coronin binding to filament sides. Different isoforms of TPM provided variable levels of protection against disassembly, with the strongest protection by Tpm3.1 and the weakest by Tpm1.6. In biomimetic assays in which filaments were simultaneously assembled by formins and disassembled by CCA, these TPM isoform–specific effects persisted, giving rise to filaments with different lengths and treadmilling behavior. Together, our data reveal that TPM isoforms have quantitatively distinct abilities to tune actin filament length and turnover.

Effects of dynamic indentation on the mechanical response of materials

2008 ◽  
Vol 23 (6) ◽  
pp. 1604-1613 ◽  
Author(s):  
M.J. Cordill ◽  
N.R. Moody ◽  
W.W. Gerberich
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Mechanical Response ◽  
Length Scale ◽  
Polycrystalline Nickel ◽  
Dynamic Indentation ◽  
Crystalline Materials ◽  
Fused Quartz ◽  
Hardness Values ◽  
Measured Hardness

Dynamic indentation techniques are often used to determine mechanical properties as a function of depth by continuously measuring the stiffness of a material. The dynamics are used by superimposing an oscillation on top of the monotonic loading. Of interest was how the oscillation affects the measured mechanical properties when compared to a quasi-static indent run at the same loading conditions as a dynamic. Single crystals of nickel and NaCl as well as a polycrystalline nickel sample and amorphous fused quartz and polycarbonate have all been studied. With respect to dynamic oscillations, the result is a decrease of the load at the same displacement and thus lower measured hardness values of the ductile crystalline materials. It has also been found that the first 100 nm of displacement are the most affected by the oscillating tip, an important length scale for testing thin films, nanopillars, and nanoparticles.

Requirement of pointed-end capping by tropomodulin to maintain actin filament length in embryonic chick cardiac myocytes

Nature ◽  
1995 ◽  
Vol 377 (6544) ◽  
pp. 83-86 ◽  
Author(s):  
Carol C. Gregorio ◽  
Annemarie Weber ◽  
Meredith Bondad ◽  
Cynthia R. Pennise ◽  
Velia M. Fowler
Keyword(s):  
Cardiac Myocytes ◽  
Actin Filament ◽  
Embryonic Chick ◽  
Filament Length ◽  
End Capping ◽  
Pointed End

scholarly journals Emergence and maintenance of different sized actin filaments in a common pool of building blocks

2021 ◽  
Author(s):  
Deb Sankar Banerjee ◽  
Shiladitya Banerjee
Keyword(s):  
Growth Inhibition ◽  
Actin Filament ◽  
Actin Filaments ◽  
Length Distribution ◽  
Building Blocks ◽  
Nucleation And Growth ◽  
Actin Binding ◽  
Filament Length ◽  
Growth Promoters ◽  
Spontaneous Nucleation

Actin is one of the key structural components of the eukaryotic cytoskeleton that regulates cellular architecture and mechanical properties. Dynamic regulation of actin filament length and organization is essential for the control of many physiological processes including cell adhesion, motility and division. While previous studies have mostly focused on the mechanisms controlling the mean length of individual actin filaments, it remains poorly understood how distinct actin filament populations in cells maintain different size using the same set of molecular building blocks. Here we develop a theoretical model for the length regulation of multiple actin filaments by nucleation and growth rate modulation by actin binding proteins in a limiting pool of monomers. We first show that spontaneous nucleation of actin filaments naturally leads to heterogeneities in filament length distribution. We then investigate the effects of filament growth inhibition by capping proteins and growth promotion by formin proteins on filament length distribution. We find that filament length heterogeneity can be increased by growth inhibition, whereas growth promoters do not significantly affect length heterogeneities. Interestingly, a competition between filament growth inhibitors and growth promoters can give rise to bimodal filament length distribution as well as a highly heterogeneous length distribution with large statistical dispersion. We quantitatively predict how heterogeneity in actin filament length can be modulated by tuning F-actin nucleation and growth rates in order to create distinct filament subpopulations with different lengths.

scholarly journals Cooperation between tropomyosin and α-actinin inhibits fimbrin association with actin filament networks in fission yeast

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Jenna R Christensen ◽  
Kaitlin E Homa ◽  
Alisha N Morganthaler ◽  
Rachel R Brown ◽  
Cristian Suarez ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Cellular Networks ◽  
Residence Time ◽  
Actin Filament ◽  
Binding Proteins ◽  
Actin Binding ◽  
Contractile Ring ◽  
Actin Networks ◽  
Filament Networks ◽  
Actin Patch

We previously discovered that competition between fission yeast actin binding proteins (ABPs) for binding F-actin facilitates their sorting to different cellular networks. Specifically, competition between endocytic actin patch ABPs fimbrin Fim1 and cofilin Adf1 enhances their activities, and prevents tropomyosin Cdc8’s association with actin patches. However, these interactions do not explain how Fim1 is prevented from associating strongly with other F-actin networks such as the contractile ring. Here, we identified α-actinin Ain1, a contractile ring ABP, as another Fim1 competitor. Fim1 competes with Ain1 for association with F-actin, which is dependent upon their F-actin residence time. While Fim1 outcompetes both Ain1 and Cdc8 individually, Cdc8 enhances the F-actin bundling activity of Ain1, allowing Ain1 to generate F-actin bundles that Cdc8 can bind in the presence of Fim1. Therefore, the combination of contractile ring ABPs Ain1 and Cdc8 is capable of inhibiting Fim1’s association with F-actin networks.

Sign in / Sign up

Export Citation Format

Share Document