scholarly journals Arabidopsis Actin Depolymerizing Factor4 Modulates the Stochastic Dynamic Behavior of Actin Filaments in the Cortical Array of Epidermal Cells

2011 ◽  
Vol 23 (10) ◽  
pp. 3711-3726 ◽  
Author(s):  
Jessica L. Henty ◽  
Samuel W. Bledsoe ◽  
Parul Khurana ◽  
Richard B. Meagher ◽  
Brad Day ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
Actin Filaments ◽  
Epidermal Cells ◽  
Stochastic Dynamic ◽  
Cortical Array

scholarly journals Guard Cell Microfilament Analyzer Facilitates the Analysis of the Organization and Dynamics of Actin Filaments in Arabidopsis Guard Cells

2019 ◽  
Vol 20 (11) ◽  
pp. 2753
Author(s):  
Xin Li ◽  
Min Diao ◽  
Yanan Zhang ◽  
Guanlin Chen ◽  
Shanjin Huang ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Dynamic Behavior ◽  
Guard Cell ◽  
Actin Filaments ◽  
De Novo ◽  
Guard Cells ◽  
Stomatal Movement ◽  
Selection Of

The actin cytoskeleton is involved in regulating stomatal movement, which forms distinct actin arrays within guard cells of stomata with different apertures. How those actin arrays are formed and maintained remains largely unexplored. Elucidation of the dynamic behavior of differently oriented actin filaments in guard cells will enhance our understanding in this regard. Here, we initially developed a program called ‘guard cell microfilament analyzer’ (GCMA) that enables the selection of individual actin filaments and analysis of their orientations semiautomatically in guard cells. We next traced the dynamics of individual actin filaments and performed careful quantification in open and closed stomata. We found that de novo nucleation of actin filaments occurs at both dorsal and ventral sides of guard cells from open and closed stomata. Interestingly, most of the nucleated actin filaments elongate radially and longitudinally in open and closed stomata, respectively. Strikingly, radial filaments tend to form bundles whereas longitudinal filaments tend to be removed by severing and depolymerization in open stomata. By contrast, longitudinal filaments tend to form bundles that are severed less frequently in closed stomata. These observations provide insights into the formation and maintenance of distinct actin arrays in guard cells in stomata of different apertures.

scholarly journals Actin filament dynamics are dominated by rapid growth and severing activity in the Arabidopsis cortical array

2009 ◽  
Vol 184 (2) ◽  
pp. 269-280 ◽  
Author(s):  
Christopher J. Staiger ◽  
Michael B. Sheahan ◽  
Parul Khurana ◽  
Xia Wang ◽  
David W. McCurdy ◽  
...  
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Stochastic Dynamics ◽  
Actin Dynamics ◽  
Epifluorescence Microscopy ◽  
Actin Assembly ◽  
Cortical Actin ◽  
Filament Dynamics ◽  
Cortical Array

Metazoan cells harness the power of actin dynamics to create cytoskeletal arrays that stimulate protrusions and drive intracellular organelle movements. In plant cells, the actin cytoskeleton is understood to participate in cell elongation; however, a detailed description and molecular mechanism(s) underpinning filament nucleation, growth, and turnover are lacking. Here, we use variable-angle epifluorescence microscopy (VAEM) to examine the organization and dynamics of the cortical cytoskeleton in growing and nongrowing epidermal cells. One population of filaments in the cortical array, which most likely represent single actin filaments, is randomly oriented and highly dynamic. These filaments grow at rates of 1.7 µm/s, but are generally short-lived. Instead of depolymerization at their ends, actin filaments are disassembled by severing activity. Remodeling of the cortical actin array also features filament buckling and straightening events. These observations indicate a mechanism inconsistent with treadmilling. Instead, cortical actin filament dynamics resemble the stochastic dynamics of an in vitro biomimetic system for actin assembly.

scholarly journals Comparison of actin and cell surface dynamics in motile fibroblasts.

1992 ◽  
Vol 119 (2) ◽  
pp. 367-377 ◽  
Author(s):  
J A Theriot ◽  
T J Mitchison
Keyword(s):  
Actin Cytoskeleton ◽  
Dynamic Behavior ◽  
Actin Filaments ◽  
Half Life ◽  
Dorsal Surface ◽  
Cell Types ◽  
3T3 Cells ◽  
3T3 Fibroblasts ◽  
Continuous Filament ◽  
Time Required

We have investigated the dynamic behavior of actin in fibroblast lamellipodia using photoactivation of fluorescence. Activated regions of caged resorufin (CR)-labeled actin in lamellipodia of IMR 90 and MC7 3T3 fibroblasts were observed to move centripetally over time. Thus in these cells, actin filaments move centripetally relative to the substrate. Rates were characteristic for each cell type; 0.66 +/- 0.27 microns/min in IMR 90 and 0.36 +/- 0.16 microns/min in MC7 3T3 cells. In neither case was there any correlation between the rate of actin movement and the rate of lamellipodial protrusion. The half-life of the activated CR-actin filaments was approximately 1 min in IMR 90 lamellipodia, and approximately 3 min in MC7 3T3 lamellipodia. Thus continuous filament turnover accompanies centripetal movement. In both cell types, the length of time required for a section of the actin meshwork to traverse the lamellipodium was several times longer than the filament half-life. The dynamic behavior of the dorsal surface of the cell was also observed by tracking lectin-coated beads on the surface and phase-dense features within lamellipodia of MC7 3T3 cells. The movement of these dorsal features occurred at rates approximately three times faster than the rate of movement of the underlying bulk actin cytoskeleton, even when measured in the same individual cells. Thus the transport of these dorsal features must occur by some mechanism other than simple attachment to the moving bulk actin cytoskeleton.

scholarly journals A Stochastic Dynamic Model of Computer Viruses

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Chunming Zhang ◽  
Yun Zhao ◽  
Yingjiang Wu ◽  
Shuwen Deng
Keyword(s):  
Numerical Simulations ◽  
Dynamic Behavior ◽  
Existence And Uniqueness ◽  
Lyapunov Functions ◽  
Computer Virus ◽  
Stochastic Dynamic ◽  
Virus Spread ◽  
Computer Viruses ◽  
Spread Model ◽  
The Stability

A stochastic computer virus spread model is proposed and its dynamic behavior is fully investigated. Specifically, we prove the existence and uniqueness of positive solutions, and the stability of the virus-free equilibrium and viral equilibrium by constructing Lyapunov functions and applying Ito's formula. Some numerical simulations are finally given to illustrate our main results.

Actin filaments line up acrossTradescantia epidermal cells, anticipating wound-induced divison planes

PROTOPLASMA ◽  
1990 ◽  
Vol 157 (1-3) ◽  
pp. 92-101 ◽  
Author(s):  
Kim C. Goodbody ◽  
C. W. Lloyd
Keyword(s):  
Actin Filaments ◽  
Epidermal Cells

scholarly journals Dynamics of Actin Filaments in Epidermal Cells of Azuki Bean Epicotyls under Hypergravity Conditions

2018 ◽  
Vol 32 (0) ◽  
pp. 11-16 ◽  
Author(s):  
Hiroyo Tanabe ◽  
Kouichi Soga ◽  
Kazuyuki Wakabayashi ◽  
Takayuki Hoson
Keyword(s):  
Actin Filaments ◽  
Epidermal Cells ◽  
Azuki Bean

Dynamic behavior of focal adhesions and associated actin filaments of sheared endothelial cells

2003 ◽  
Vol 2003.5 (0) ◽  
pp. 33-34
Author(s):  
Toshiro OHASHI ◽  
Tsugumasa YAMAMOTO ◽  
Naoki MOCHIZUKI ◽  
Masaaki SATO
Keyword(s):  
Endothelial Cells ◽  
Dynamic Behavior ◽  
Actin Filaments ◽  
Focal Adhesions

scholarly journals Role of fascin in filopodial protrusion

2006 ◽  
Vol 174 (6) ◽  
pp. 863-875 ◽  
Author(s):  
Danijela Vignjevic ◽  
Shin-ichiro Kojima ◽  
Yvonne Aratyn ◽  
Oana Danciu ◽  
Tatyana Svitkina ◽  
...  
Keyword(s):  
Rna Interference ◽  
Dynamic Behavior ◽  
Actin Filaments ◽  
Cellular Localization ◽  
Fluorescence Recovery After Photobleaching ◽  
Cross Linking ◽  
Wild Type ◽  
Actin Organization ◽  
Cross Linker

In this study, the mechanisms of actin-bundling in filopodia were examined. Analysis of cellular localization of known actin cross-linking proteins in mouse melanoma B16F1 cells revealed that fascin was specifically localized along the entire length of all filopodia, whereas other actin cross-linkers were not. RNA interference of fascin reduced the number of filopodia, and remaining filopodia had abnormal morphology with wavy and loosely bundled actin organization. Dephosphorylation of serine 39 likely determined cellular filopodia frequency. The constitutively active fascin mutant S39A increased the number and length of filopodia, whereas the inactive fascin mutant S39E reduced filopodia frequency. Fluorescence recovery after photobleaching of GFP-tagged wild-type and S39A fascin showed that dephosphorylated fascin underwent rapid cycles of association to and dissociation from actin filaments in filopodia, with t1/2 < 10 s. We propose that fascin is a key specific actin cross-linker, providing stiffness for filopodial bundles, and that its dynamic behavior allows for efficient coordination between elongation and bundling of filopodial actin filaments.

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