Agudo-Canalejo Jaime
Max Planck Institute for Dynamics and Self-Organization (MPIDS), D-37077 Göttingen, Germany.
Soft Matter. 2021 Jan 22;17(2):298-307. doi: 10.1039/c9sm02367d.
Biological cells are capable of undergoing extensive shape transformations thanks to the existence of membrane area reservoirs from which they can pull out membrane when required. A particularly relevant example of such membrane remodelling is given by endocytic and phagocytic processes, during which the cell membrane engulfs nano- and micrometer sized particles. Recently, it was shown that cell-like membrane reservoirs can be mimicked in giant vesicles with nanotubes stabilized by strong bilayer asymmetry, as quantified by the membrane's spontaneous curvature. Here, we theoretically investigate particle engulfment by such strongly-asymmetric membranes. We find that, depending on the sign of the spontaneous curvature, the engulfment transition may be continuous or discontinuous. Moreover, we find that, in the case of particle engulfment, the presence of asymmetry-stabilized reservoirs is not well captured by the constant-tension model typically used to describe cell-membrane deformations. This highlights the need for a better understanding of the nature of cellular membrane reservoirs, in order to accurately describe membrane remodelling processes.
由于存在膜面积储备库，生物细胞能够进行广泛的形状转变，当需要时它们可以从储备库中抽出膜。这种膜重塑的一个特别相关的例子是内吞和吞噬过程，在此过程中细胞膜会吞噬纳米和微米大小的颗粒。最近的研究表明，通过具有由强双层不对称性稳定的纳米管的巨型囊泡可以模拟细胞样膜储备库，这种不对称性由膜的自发曲率来量化。在此，我们从理论上研究了这种强不对称膜对颗粒的吞噬作用。我们发现，根据自发曲率的符号，吞噬转变可能是连续的或不连续的。此外，我们还发现，在颗粒吞噬的情况下，通常用于描述细胞膜变形的恒张力模型并不能很好地捕捉到由不对称性稳定的储备库的存在。这凸显了为准确描述膜重塑过程而更好地理解细胞膜储备库性质的必要性。
