Vogel Sven Kenjiro, Greiss Ferdinand, Khmelinskaia Alena, Schwille Petra
Max-Planck Institute of Biochemistry, Martinsried, Germany.
Systems Biophysics, Physics Department, Ludwig-Maximilans-University, Munich, Germany.
Elife. 2017 May 2;6:e24350. doi: 10.7554/eLife.24350.
The cell membrane is a heterogeneously organized composite with lipid-protein micro-domains. The contractile actin cortex may govern the lateral organization of these domains in the cell membrane, yet the underlying mechanisms are not known. We recently reconstituted minimal actin cortices (MACs) (Vogel et al., 2013b) and here advanced our assay to investigate effects of rearranging actin filaments on the lateral membrane organization by introducing various phase-separated lipid mono- and bilayers to the MACs. The addition of actin filaments reorganized membrane domains. We found that the process reached a steady state where line tension and lateral crowding balanced. Moreover, the phase boundary allowed myosin driven actin filament rearrangements to actively move individual lipid domains, often accompanied by their shape change, fusion or splitting. Our findings illustrate how actin cortex remodeling in cells may control dynamic rearrangements of lipids and other molecules inside domains without directly binding to actin filaments.
细胞膜是一种具有脂质 - 蛋白质微结构域的异质组织复合物。收缩性肌动蛋白皮层可能控制细胞膜中这些结构域的侧向组织，但其潜在机制尚不清楚。我们最近重建了最小肌动蛋白皮层（MACs）（Vogel等人，2013b），并在此改进了我们的实验方法，通过向MACs中引入各种相分离的脂质单层和双层来研究肌动蛋白丝重排对侧向膜组织的影响。肌动蛋白丝的添加重组了膜结构域。我们发现该过程达到了一个稳态，其中线张力和侧向拥挤达到平衡。此外，相边界允许肌球蛋白驱动的肌动蛋白丝重排主动移动单个脂质结构域，通常伴随着它们的形状变化、融合或分裂。我们的研究结果说明了细胞中的肌动蛋白皮层重塑如何在不直接结合肌动蛋白丝的情况下控制结构域内脂质和其他分子的动态重排。
