arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1512.03418cond-mat.softcond-mat.stat-mech
收藏

活跃的过程使混合脂膜要么平坦要么起皱

Active processes make mixed lipid membranes either flat or crumpled

Tirthankar Banerjee, Abhik Basu

摘要:

活细胞膜是否表现出可折叠性相变(MPTs),如果是这样,它们在相变附近如何波动仍然是物理学和生物学中悬而未决的问题。受这些问题的启发,我们构建了脂膜的通用流体动力学理论(脂膜是活跃的,例如,由于周围细胞骨架中的分子马达,或膜本身中的活性蛋白质组分)。我们利用这一点来揭示膜波动和MPTs之间的直接对应关系。几个可测试的预测:(i)通用{ \em主动硬化}与取向长程序(平膜)或{ \em软化}与膜的褶皱,由{ \em主动张力}控制和(ii)对于混合脂质膜,捕获的性质推定MPTS通过测量膜构象波动。混合活性膜中可能存在一级和二级MPTs。接近二级MPT时,主动硬化(软化)表现为{ \em超硬(超软)膜}。我们的预测在各种{ \em体外}系统中是可检验的,例如,沉积在脂质体和脂质膜上的活细胞骨架提取物,其中含有包埋在被动流体中的活性蛋白质。

英文摘要:

Whether live cell membranes show miscibility phase transitions (MPTs), and if so, how they fluctuate near the transitions remain outstanding unresolved issues in physics and biology alike. Motivated by these questions we construct a generic hydrodynamic theory for lipid membranes {that are active, due for instance, to the molecular motors in the surrounding cytoskeleton, or active protein components in the membrane itself}. We use this to uncover a direct correspondence between membrane fluctuations and MPTs. Several testable predictions are made: (i) generic {\em active stiffening} with orientational long range order (flat membrane) or {\em softening} with crumpling of the membrane, controlled by the {\em active tension} and (ii) for mixed lipid membranes, capturing the nature of putative MPTs by measuring the membrane conformation fluctuations. Possibilities of both first and second order MPTs in mixed active membranes are argued for. Near second order MPTs, active stiffening (softening) manifests as a {\em super-stiff (super-soft) membrane}. Our predictions are testable in a variety of {\em in-vitro} systems, e.g., live cytoskeletal extracts deposited on liposomes and lipid membranes containing active proteins embedded in a passive fluid.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑