Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, Gower Street, London, WC1E 6BT, UK.
Soft Matter. 2017 Jul 19;13(28):4924-4930. doi: 10.1039/c7sm00433h.
Cellular membranes exhibit a large variety of shapes, strongly coupled to their function. Many biological processes involve dynamic reshaping of membranes, usually mediated by proteins. This interaction works both ways: while proteins influence the membrane shape, the membrane shape affects the interactions between the proteins. To study these membrane-mediated interactions on closed and anisotropically curved membranes, we use colloids adhered to ellipsoidal membrane vesicles as a model system. We find that two particles on a closed system always attract each other, and tend to align with the direction of largest curvature. Multiple particles form arcs, or, at large enough numbers, a complete ring surrounding the vesicle in its equatorial plane. The resulting vesicle shape resembles a snowman. Our results indicate that these physical interactions on membranes with anisotropic shapes can be exploited by cells to drive macromolecules to preferred regions of cellular or intracellular membranes, and utilized to initiate dynamic processes such as cell division. The same principle could be used to find the midplane of an artificial vesicle, as a first step towards dividing it into two equal parts.
细胞膜表现出多种多样的形状，这些形状与它们的功能密切相关。许多生物过程涉及到膜的动态重塑，通常是由蛋白质介导的。这种相互作用是双向的：一方面，蛋白质影响膜的形状；另一方面，膜的形状也影响蛋白质之间的相互作用。为了在封闭的各向异性弯曲的膜上研究这些膜介导的相互作用，我们使用附着在椭圆形膜泡上的胶体作为模型系统。我们发现，在封闭系统中，两个粒子总是相互吸引，并倾向于沿着曲率最大的方向排列。多个粒子形成弧形，或者在足够多的粒子情况下，在膜泡赤道平面上形成一个完整的环，环绕在膜泡周围。由此产生的膜泡形状类似于一个雪人。我们的结果表明，这些具有各向异性形状的膜上的物理相互作用可以被细胞用来将大分子驱动到细胞或细胞内膜的优选区域，并利用这些相互作用来启动诸如细胞分裂等动态过程。同样的原理也可以用来找到人工膜泡的中平面，作为将其分成两个相等部分的第一步。
