Laboratoire de Physique Théorique et Modèles Statistiques

Semianire LPTMS: Martin Lenz (Chicago)

Cross-linking actin into function

Martin Lenz, James Franck Institute, Université de Chicago

Actin filaments are paramount players in the shaping and dynamics of eukaryotic cells, and can form a variety of structures as they are regulated by a host of associated proteins. Here we focus on some spectacular examples of such constructs: stereocilia and stress fibers, which are bundles formed under the influence of actin cross-linking proteins. The relatively large scale of these structures implies that their overall organization crucially involves the collective behavior of actin and its cross-linkers, into which a theoretical approach yields some interesting insights.

We first propose that the cross-linker espin may regulate the shape of stereocilia, which are protrusions of cells of the inner ear crucial for hearing. Very good agreement with a range of experimental results is obtained by fitting only one parameter: the detachment rate of espin. Our model displays a transition from finite-length structures to unbounded growth, some universal features of which could help classify cellular growth processes. We next focus on biomimetic bundles containing the cross-linking motor myosin. We show that the widely accepted filament sliding model is not sufficient to predict whether these bundles tend to extend or contract, whereas the latter is always observed experimentally. We explore the hypothesis that this symmetry could be broken through the nonlinear elastic behavior of actin filaments.

Mardi 22 Juin à 11h

LPTMS-batiment 100, salle 201, Orsay


Calendrier des séminaires

Mai
Juillet
Juin 2010
lun. mar. mer. jeu. ven.
 
1
16:00» Seminaire LPTMS: Uzy Smilansky (Weizmann)
2
3
14:00» Séminaire commun LPT-LPTMS : Petr Sulc
4
11:00» Séminaire du LPTMS : Yoshiyuki Kabashima
7
14:00» Séminaire PHYSTAT-SUD : Jon Keating
8
11:00» Seminaire LPTMS : Luigi Cantini (LPT ENS)
9
10
11
14
15
11:00» Seminaire LPTMS: Rhoda Hawkins
16
17
18
14:00» Séminaire Physique Biologique et Systèmes Complexes : Guillaume Romet-Lemonne
21
22
11:00» Semianire LPTMS: Martin Lenz (Chicago)
23
24
16:00» Séminaire du LPTMS : Gunnar Boldhaus
25
10:30» Soutenance de thèse : Carlos Eduardo Alvarez Cabrera
15:00» Séminaire exceptionnel du LPTMS : Paolo Solinas
28
29
11:00» Seminaire LPTMS: Celine Nadal, Alvaro Rojo
30