文章基本信息

标题：Two competing orientation patterns explain experimentally observed anomalies in growing actin networks
本地全文：下载
作者：Julian Weichsel ; Ulrich S. Schwarz
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：14
页码：6304-6309
DOI：10.1073/pnas.0913730107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The lamellipodium of migrating animal cells protrudes by directed polymerization of a branched actin network. The underlying mechanisms of filament growth, branching, and capping can be studied in in vitro assays. However, conflicting results have been reported for the force-velocity relation of such actin networks, namely both convex and concave shapes as well as history dependencies. Here we model branching as a reaction that is independent of the number of existing filaments, in contrast to capping, which is assumed to be proportional to the number of existing filaments. Using both stochastic network simulations and deterministic rate equations, we show that such a description naturally leads to the stability of two qualitatively different stationary states of the system, namely a {+/-} 35{degrees} and a +70/0/-70{degrees} orientation pattern. Changes in network growth velocity induce a transition between these two patterns. For sufficiently different protrusion efficiency of the two network architectures, this leads to hysteresis in the growth velocity of actin networks under force. Dependent on the history of the system, convex and concave regimes are obtained for the force-velocity relation. Thus a simple generic model can explain the experimentally observed anomalies, with far reaching consequences for cell migration.
关键词：cytoskeleton ; cell motility ; stochastic simulations ; rate equations