contraction mechanisms in composite active actin networks收缩机制复合活性肌动蛋白网络.pdfVIP

Contraction Mechanisms in Composite Active Actin Networks ¨ Simone Kohler, Andreas R. Bausch* ¨ ¨ ¨ Lehrstuhl fur Biophysik E27, Technische Universitat Munchen, Garching, Germany Abstract Simplified in vitro systems are ideally suited for studying the principle mechanisms of the contraction of cytoskeletal actin systems. To shed light on the dependence of the contraction mechanism on the nature of the crosslinking proteins, we study reconstituted in vitro active actin networks on different length scales ranging from the molecular organization to the macroscopic contraction. Distinct contraction mechanisms are observed in polar and apolar crosslinked active gels whereas composite active gels crosslinked in a polar and apolar fashion at the same time exhibit both mechanisms simultaneously. In polar active actin/fascin networks initially bundles are formed which are then rearranged. In contrast, apolar cortexillin-I crosslinked active gels are bundled only after reorganization of actin filaments by myosin-II motor filaments. ¨ Citation: Kohler S, Bausch AR (2012) Contraction Mechanisms in Composite Active Actin Networks. PLoS ONE 7(7): e39869. doi:10.1371/journal.pone.0039869 Editor: Harry Mellor, University of Bristol, United Kingdom Received April 3, 2012; Accepted May 28, 2012; Published July 2, 2012 ¨ Copyright: 2012 Kohler, Bausch. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: Financial support from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC CompNet (279476) is gratefully acknowledged. The