Limits...
Force-induced dynamical properties of multiple cytoskeletal filaments are distinct from that of single filaments.

Das D, Das D, Padinhateeri R - PLoS ONE (2014)

Bottom Line: Comparing stochastic simulation results with recent experimental data, we show that multi-filament collective catastrophes are slower than catastrophes of single filaments.We build a unified picture by establishing interconnections among all these collective phenomena.Additionally, we show that the collapse times during catastrophes can be sharp indicators of collective stall forces exceeding the additive contributions of single filaments.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.

ABSTRACT
How cytoskeletal filaments collectively undergo growth and shrinkage is an intriguing question. Collective properties of multiple bio-filaments (actin or microtubules) undergoing hydrolysis have not been studied extensively earlier within simple theoretical frameworks. In this paper, we study the collective dynamical properties of multiple filaments under force, and demonstrate the distinct properties of a multi-filament system in comparison to a single filament. Comparing stochastic simulation results with recent experimental data, we show that multi-filament collective catastrophes are slower than catastrophes of single filaments. Our study also shows further distinctions as follows: (i) force-dependence of the cap-size distribution of multiple filaments are quantitatively different from that of single filaments, (ii) the diffusion constant associated with the system length fluctuations is distinct for multiple filaments, and (iii) switching dynamics of multiple filaments between capped and uncapped states and the fluctuations therein are also distinct. We build a unified picture by establishing interconnections among all these collective phenomena. Additionally, we show that the collapse times during catastrophes can be sharp indicators of collective stall forces exceeding the additive contributions of single filaments.

Show MeSH

Related in: MedlinePlus

Few time traces of  of the leader for (a)  and (b)  actin filaments, at a concentration  and at different values of scaled forces.At these forces, the corresponding values of wall-diffusion coefficient  are shown by arrows in Fig. 8a (red arrows for  and green arrows for ).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4273989&req=5

pone-0114014-g009: Few time traces of of the leader for (a) and (b) actin filaments, at a concentration and at different values of scaled forces.At these forces, the corresponding values of wall-diffusion coefficient are shown by arrows in Fig. 8a (red arrows for and green arrows for ).

Mentions: In Fig. 9a we show the time traces of for a single actin filament at different force values – at these forces, the corresponding values of wall-diffusion constant D are shown by red arrows in Fig. 8a. We see that, at the filament is mostly in the capped state – (mostly) in top panel (i) of Fig. 9a. When is just above , we see in panel (ii) of Fig. 9a, that there is a sudden increase in the number of switching events between capped and uncapped states. If is increased further, the number of switching events decreases – see subsequent panels (iii) and (iv). So, the number of switching events first increases, and then decreases with force. Note that this behavior mimics the non-monotonic behavior of the wall-diffusion constant D, for (see Fig. 8a). Moreover, the bottom panel (iv) of Fig. 9a, where is mostly 0, signifies that the filament is capless (also see Fig. 6).


Force-induced dynamical properties of multiple cytoskeletal filaments are distinct from that of single filaments.

Das D, Das D, Padinhateeri R - PLoS ONE (2014)

Few time traces of  of the leader for (a)  and (b)  actin filaments, at a concentration  and at different values of scaled forces.At these forces, the corresponding values of wall-diffusion coefficient  are shown by arrows in Fig. 8a (red arrows for  and green arrows for ).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4273989&req=5

pone-0114014-g009: Few time traces of of the leader for (a) and (b) actin filaments, at a concentration and at different values of scaled forces.At these forces, the corresponding values of wall-diffusion coefficient are shown by arrows in Fig. 8a (red arrows for and green arrows for ).
Mentions: In Fig. 9a we show the time traces of for a single actin filament at different force values – at these forces, the corresponding values of wall-diffusion constant D are shown by red arrows in Fig. 8a. We see that, at the filament is mostly in the capped state – (mostly) in top panel (i) of Fig. 9a. When is just above , we see in panel (ii) of Fig. 9a, that there is a sudden increase in the number of switching events between capped and uncapped states. If is increased further, the number of switching events decreases – see subsequent panels (iii) and (iv). So, the number of switching events first increases, and then decreases with force. Note that this behavior mimics the non-monotonic behavior of the wall-diffusion constant D, for (see Fig. 8a). Moreover, the bottom panel (iv) of Fig. 9a, where is mostly 0, signifies that the filament is capless (also see Fig. 6).

Bottom Line: Comparing stochastic simulation results with recent experimental data, we show that multi-filament collective catastrophes are slower than catastrophes of single filaments.We build a unified picture by establishing interconnections among all these collective phenomena.Additionally, we show that the collapse times during catastrophes can be sharp indicators of collective stall forces exceeding the additive contributions of single filaments.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, India.

ABSTRACT
How cytoskeletal filaments collectively undergo growth and shrinkage is an intriguing question. Collective properties of multiple bio-filaments (actin or microtubules) undergoing hydrolysis have not been studied extensively earlier within simple theoretical frameworks. In this paper, we study the collective dynamical properties of multiple filaments under force, and demonstrate the distinct properties of a multi-filament system in comparison to a single filament. Comparing stochastic simulation results with recent experimental data, we show that multi-filament collective catastrophes are slower than catastrophes of single filaments. Our study also shows further distinctions as follows: (i) force-dependence of the cap-size distribution of multiple filaments are quantitatively different from that of single filaments, (ii) the diffusion constant associated with the system length fluctuations is distinct for multiple filaments, and (iii) switching dynamics of multiple filaments between capped and uncapped states and the fluctuations therein are also distinct. We build a unified picture by establishing interconnections among all these collective phenomena. Additionally, we show that the collapse times during catastrophes can be sharp indicators of collective stall forces exceeding the additive contributions of single filaments.

Show MeSH
Related in: MedlinePlus