MECHANICAL-PROPERTIES OF NEURONAL GROWTH CONE MEMBRANES STUDIED BY TETHER FORMATION WITH LASER OPTICAL TWEEZERS
MECHANICAL-PROPERTIES OF NEURONAL GROWTH CONE MEMBRANES STUDIED BY TETHER FORMATION WITH LASER OPTICAL TWEEZERS
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DOI：
10.1016/s0006-3495(95)80274-2
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发表时间：
1995-03-01
影响因子：
3.4
通讯作者：
SHEETZ, MP
中科院分区：
文献类型：
--
作者：
DAI, JW;SHEETZ, MP
许多细胞现象涉及重大的形态变化，特别是在有丝分裂和细胞迁移过程中。为了使细胞或神经元生长锥体迁移，它们必须将质膜的前沿延伸为片状基座或丝状基座。在丝状孢子延伸的过程中，膜必须穿过表面移动，产生剪切和流动。驱动延伸的细胞内生化过程必须违背膜的机械性能，但延伸生长锥体所需的力尚未被测量。本文利用激光光钳和纳米级分析系统，通过对包覆有免疫球蛋白微珠的视锥状系绳的拉伸，测量了神经元生长锥膜的力学性能。尽管珠子附着在细胞膜上的概率是恒定的，但在细胞松弛素B或D和二甲基亚砜(DMSO)的作用下，形成恒定力的系绳的概率显著增加。这些治疗方法可以改变肌动蛋白细胞骨架的组织。以零速度握持系绳所需的力(F-0)大于单分子马达、动蛋白和肌球蛋白产生的力；而F随细胞松弛素B或D和DMSO的变化而减小，与系绳形成概率的变化有关。系绳对钢珠的作用力随着系绳伸长速度的增加而线性增加。根据系缆力对系绳形成速度的依赖关系，我们计算了一个与膜粘度有关的参数，该参数随细胞松弛素B或D、三磷酸腺苷耗竭、诺可唑和二甲基亚砜的减少而降低。这些结果表明，肌动蛋白细胞骨架影响膜的力学性能，包括膜拉伸所需的力和粘弹性行为。
Many cell phenomena involve major morphological changes, particularly in mitosis and the process of cell migration. For cells or neuronal growth cones to migrate, they must extend the leading edge of the plasma membrane as a lamellipodium or filopodium. During extension of filopodia, membrane must move across the surface creating shear and flow. Intracellular biochemical processes driving extension must work against the membrane mechanical properties, but the forces required to extend growth cones have not been measured. In this paper, laser optical tweezers and a nanometer-level analysis system were used to measure the neuronal growth cone membrane mechanical properties th rough the extension of fi loped ia-like tethers with IgG-coated beads. Although the probability of a bead attaching to the membrane was constant irrespective of treatment; the probability of forming a tether with a constant force increased dramatically with cytochalasin B or D and dimethylsulfoxide (DMSO). These are treatments that alter the organization of the actin cytoskeleton. The force required to hold a tether at zero velocity (F-0) was greater than forces generated by single molecular motors, kinesin and myosin; and F, decreased with cytochalasin B or D and DMSO in correlation with the changes in the probability of tether formation. The force of the tether on the bead increased linearly with the velocity of tether elongation. From the dependency of tether force on velocity of tether formation, we calculated a parameter related to membrane viscosity, which decreased with cytochalasin B or D, ATP depletion, nocodazole, and DMSO. These results indicate that the actin cytoskeleton affects the membrane mechanical properties, including the force required for membrane extension and the viscoelastic behavior.