Department of Chemical Engineering, Columbia University, New York, New York 10027, USA.
Phys Rev Lett. 2012 Apr 27;108(17):178101. doi: 10.1103/PhysRevLett.108.178101. Epub 2012 Apr 23.
Fusion of compartments enclosed by membrane bilayers enables secretion and other vital cellular processes and is widely studied in model synthetic membrane systems. Experiments suggest the fusion pathway passes through a hemifused intermediate where only outer monolayers are fused. Here we show membrane tension and divalent cations drive vesicles to hemifused equilibrium with expanded hemifusion diaphragms (HDs) where inner monolayers engage. Predicted HD sizes agree with recent measurements of Nikolaus et al. [Biophys. J. 98, 1192 (2010).]. The fusion pathway is completed by HD lysis provided HD tension is sufficiently high.
膜双层所包围的隔室融合使分泌和其他重要的细胞过程成为可能，并在模型合成膜系统中得到了广泛的研究。实验表明，融合途径通过一个半融合中间体进行，其中只有外层单层融合。在这里，我们展示了膜张力和二价阳离子驱动囊泡达到半融合平衡，此时内单层参与其中，并形成扩展的半融合隔膜（HD）。预测的 HD 大小与 Nikolaus 等人最近的测量结果一致[Biophys. J. 98, 1192 (2010).]。只要 HD 张力足够高，HD 的裂解就能完成融合途径。
