生物谷报道：细胞膜远不止是细胞外的一层包裹物，对其拓扑进行的重塑研究，将它们与内吞作用、囊泡形成和蛋白分选等重要功能联系了起来。专门的蛋白能够感知和生成膜曲率，指导膜的重塑。几种蛋白需要一起发挥作用才能完成这一任务，所以一种比较普遍的效应被认为也在发挥作用。多年来，物理学家、数学家、材料科学家和细胞生物学家对一种可能的普遍作用——完全由膜曲率诱导的蛋白之间的吸引力进行了研究。但是，诱导蛋白间相互作用的膜曲率的性质，甚至它们之间的相互作用是吸引还是排斥都仍然比较模糊。现在，计算机模拟显示，曲率诱导的相互作用的确可以是一种吸引力，并且是强大的、很有力的吸引力，完全能够胜任影响膜重塑的任务。本期封面图片所示为一个在协同分裂期间被衣壳所覆盖的虚拟细胞膜。
英文原文：
Letter
Nature 447, 461-464 (24 May 2007) | doi:10.1038/nature05840; Received 23 October 2006; Accepted 11 April 2007
Aggregation and vesiculation of membrane proteins by curvature-mediated interactions
Benedict J. Reynwar1, Gregoria Illya1, Vagelis A. Harmandaris1, Martin M. Müller1, Kurt Kremer1 & Markus Deserno1
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
Correspondence to: Kurt Kremer1Markus Deserno1 Correspondence and requests for materials should be addressed to M.D. (Email: deserno@mpip-mainz.mpg.de) or K.K. (Email: kremer@mpip-mainz.mpg.de).
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Membrane remodelling1, 2, 3, 4, 5 plays an important role in cellular tasks such as endocytosis, vesiculation and protein sorting, and in the biogenesis of organelles such as the endoplasmic reticulum or the Golgi apparatus. It is well established that the remodelling process is aided by specialized proteins that can sense4 as well as create6 membrane curvature, and trigger tubulation7, 8, 9 when added to synthetic liposomes. Because the energy needed for such large-scale changes in membrane geometry significantly exceeds the binding energy between individual proteins and between protein and membrane, cooperative action is essential. It has recently been suggested10, 11 that curvature-mediated attractive interactions could aid cooperation and complement the effects of specific binding events on membrane remodelling. But it is difficult to experimentally isolate curvature-mediated interactions from direct attractions between proteins. Moreover, approximate theories predict repulsion between isotropically curving proteins12, 13, 14, 15. Here we use coarse-grained membrane simulations to show that curvature-inducing model proteins adsorbed on lipid bilayer membranes can experience attractive interactions that arise purely as a result of membrane curvature. We find that once a minimal local bending is realized, the effect robustly drives protein cluster formation and subsequent transformation into vesicles with radii that correlate with the local curvature imprint. Owing to its universal nature, curvature-mediated attraction can operate even between proteins lacking any specific interactions, such as newly synthesized and still immature membrane proteins in the endoplasmic reticulum.
