Confotronics Of Bio-filaments
Lundi 11 mai 2015 14:00
- Duree : 1 heure
Lieu : Conference room - LIPhy - Bât E - 140 Avenue de la Physique - St Martin d’Hères. Accès par interphone, appeler le secrétariat
Orateur : Hervé MOHRBACH (Equipe BioPhysStat, Université de Lorraine, Metz)
Many biofilaments, like those of the cytoskeleton, show anomalous behaviors in various experiments. As we will show, this can be explained by the existence of internal degrees of freedom, usually inaccessible by direct observation, but crucial for the understanding of the collective dynamics of the biofilaments. This is the case for coiled helices squeezed flat onto two-dimensional surfaces. Under such 2-d confinement, helices form “squeelices”—peculiar squeezed conformations often resembling looped waves, spirals or circles. The shapes as well as the unusual statistical mechanics of squeelices can be understood in terms of moving and interacting localized conformational quasiparticles called the “twist kinks”. These theoretical results will be interpreted in the light of recent experiments realized on actin and intermediate filaments.
As a second example, we will consider tubular lattices like microtubules. We will see that when prestress is introduced in such structures, localized conformational quasiparticles called “confloplexes” emerge and govern the collective shape dynamics of the lattice via elastically-mediated interactions. This allows to understand the anomalous elastic and dynamic behavior of microtubules. In particular, we will give an explanation for the formation of gliding microtubule arcs and rings in kinesin-driven gliding assays.
Contact : catherine.quilliet@ujf-grenoble.fr
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