Jia Haiyang, Litschel Thomas, Heymann Michael, Eto Hiromune, Franquelim Henri G, Schwille Petra
Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried, D-82152, Germany.
Small. 2020 Jul;16(27):e1906259. doi: 10.1002/smll.201906259. Epub 2020 Feb 27.
Giant unilamellar phospholipid vesicles are attractive starting points for constructing minimal living cells from the bottom-up. Their membranes are compatible with many physiologically functional modules and act as selective barriers, while retaining a high morphological flexibility. However, their spherical shape renders them rather inappropriate to study phenomena that are based on distinct cell shape and polarity, such as cell division. Here, a microscale device based on 3D printed protein hydrogel is introduced to induce pH-stimulated reversible shape changes in trapped vesicles without compromising their free-standing membranes. Deformations of spheres to at least twice their aspect ratio, but also toward unusual quadratic or triangular shapes can be accomplished. Mechanical force induced by the cages to phase-separated membrane vesicles can lead to spontaneous shape deformations, from the recurrent formation of dumbbells with curved necks between domains to full budding of membrane domains as separate vesicles. Moreover, shape-tunable vesicles are particularly desirable when reconstituting geometry-sensitive protein networks, such as reaction-diffusion systems. In particular, vesicle shape changes allow to switch between different modes of self-organized protein oscillations within, and thus, to influence reaction networks directly by external mechanical cues.
巨型单层磷脂囊泡是自下而上构建最小化活细胞的有吸引力的起始点。它们的膜与许多生理功能模块兼容，并作为选择性屏障，同时保持高度的形态灵活性。然而，它们的球形形状使其不太适合研究基于独特细胞形状和极性的现象，如细胞分裂。在此，引入了一种基于3D打印蛋白质水凝胶的微尺度装置，以在不损害其独立膜的情况下诱导捕获的囊泡发生pH刺激的可逆形状变化。可以实现球体至少变为其纵横比两倍的变形，还可以变为不寻常的方形或三角形形状。笼子对相分离膜囊泡施加的机械力可导致自发形状变形，从在区域之间反复形成带有弯曲颈部的哑铃状，到膜区域完全出芽形成单独的囊泡。此外，在重构几何形状敏感的蛋白质网络（如反应扩散系统）时，形状可调的囊泡尤为可取。特别是，囊泡形状变化允许在其内部不同的自组织蛋白质振荡模式之间切换，从而通过外部机械线索直接影响反应网络。
