Berlin 2015 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 63: Cytoskeletal filaments (Joint session BP, CPP)
CPP 63.8: Vortrag
Donnerstag, 19. März 2015, 12:00–12:15, H 1028
Spontaneous polarization in an interfacial growth model for actin filament networks with a rigorous mechanochemical coupling — •Karin John1, Denis Caillerie2, Thomas Stoeter1,3, and Chaouqi Misbah1 — 1Université Grenoble Alpes/ CNRS, LIPHY, F-38000 Grenoble, France — 2Université Grenoble Alpes/CNRS, 3SR, F-38000 Grenoble, France — 3Otto-von-Guericke Universität Magdeburg
Many processes in eukaryotic cells, including cell motility, rely on the growth of branched actin networks from surfaces. Despite its central role the mechanochemical coupling mechanisms that guide the growth process are poorly understood, and a general continuum description combining growth and mechanics is lacking. We develop a theory that bridges the gap between mesoscale and continuum limit and propose a general framework providing the evolution law of actin networks growing under stress. This formulation opens an area for the systematic study of actin dynamics in arbitrary geometries. Our framework predicts a morphological instability of actin growth on a rigid sphere, leading to a spontaneous polarization of the network with a mode selection corresponding to a comet, as reported experimentally. We show that the mechanics of the contact between the network and the surface plays a crucial role, in that it determines directly the existence of the instability. We extract scaling laws relating growth dynamics and network properties offering basic perspectives for new experiments on growing actin networks.