9-13 July 2012
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=11&confId=14"><font color=#ff0000>SAIP2012 PROCEEDINGS AVAILABLE</font></a>

Elastic response of lament networks with active cross-links

13 Jul 2012, 08:40
20m
IT 4-4

IT 4-4

Oral Presentation Track G - Theoretical and Computational Physics Biophysics

Speaker

Prof. Kristian Müller-Nedebock (Inst. of Theoretical Physics, Dept of Physics, Stellenbosch University)

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

N/A

Abstract content <br> &nbsp; (Max 300 words)

Force and directed motion can be generated by molecular machines on associated laments. Examples of cytoskeletal constituents include kinesins on microtubules. We present a theoretical study of pre-existing, permanent networks of such laments that are cross-linked by linkers consisting of pairs of molecular motors (in addition to the usual permanent, stationary cross-links). First considering the motors as having a translational degree of freedom along the laments, but unable to detach, both the static modications to the elastic response of the network as a function of the motor force as well as the dynamic fluctuations of the cross-linker positions in a steady state of the motors can be calculated in approximations for small forces. For the static case we develop a quasi-equilibrium point of view utilising the replica method to treat the disorder. In the latter dynamic scenario we employ a functional integral approach with appropriate Langevin equations. Secondly, we include the possibility that motors are not permanently attached to the laments. We show how a eld-theoretical technique [R. Fantoni, K.K. Müller-Nedebock, Phys. Rev. E 84 011808 (2011)] enables the inclusion of attachment-detachment statistics of the active cross-links into the formalism. The eld theory also leads to a natural collective formulation for these active systems.

Main supervisor (name and email)<br>and his / her institution

N/A

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

No

Apply to be<br> consider for a student <br> &nbsp; award (Yes / No)?

No

Primary author

Prof. Kristian Müller-Nedebock (Inst. of Theoretical Physics, Dept of Physics, Stellenbosch University)

Co-authors

J.M. Mateyisi (Inst. of Theoretical Physics, Dept of Physics, Stellenbosch University) K. Möller (Inst. of Theoretical Physics, Dept of Physics, Stellenbosch University) L. Boonzaaier (Inst. of Theoretical Physics, Dept of Physics, Stellenbosch University)

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