Noguchi Hiroshi
Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Soft Matter. 2021 Dec 1;17(46):10469-10478. doi: 10.1039/d1sm01360b.
A tethered vesicle, which consists of a cylindrical membrane tube and a spherical vesicle, is produced by a mechanical force that is experimentally imposed by optical tweezers and a micropipette. This tethered vesicle is employed for examining the curvature sensing of curvature-inducing proteins. In this study, we clarify how the binding of proteins with a laterally isotropic spontaneous curvature senses and generates the membrane curvatures of the tethered vesicle using mean-field theory and meshless membrane simulation. The force-dependence curves of the protein density in the membrane tube and the tube curvature are reflection symmetric and point symmetric, respectively, from the force point, in which the tube has a sensing curvature. The bending rigidity and spontaneous curvature of the bound proteins can be estimated from these force-dependence curves. First-order transitions can occur between low and high protein densities in the tube at both low and high force amplitudes. The simulation results of the homogeneous phases agree very well with the theoretical predictions. In addition, beaded-necklace-like tubes with microphase separation are found in the simulation.
一种由圆柱形膜管和球形囊泡组成的束缚囊泡，是通过光镊和微量移液器实验施加的机械力产生的。这种束缚囊泡用于研究曲率诱导蛋白的曲率传感。在本研究中，我们使用平均场理论和无网格膜模拟，阐明了具有横向各向同性自发曲率的蛋白质的结合如何感知并产生束缚囊泡的膜曲率。膜管中蛋白质密度与管曲率的力依赖曲线分别从管具有传感曲率的力点起呈反射对称和点对称。结合蛋白的弯曲刚度和自发曲率可从这些力依赖曲线估计。在低力幅和高力幅下，管内低蛋白密度和高蛋白密度之间都可能发生一级转变。均匀相的模拟结果与理论预测非常吻合。此外，在模拟中发现了具有微相分离的串珠项链状管。
