Lateral electrophoresis and diffusion of Concanavalin A receptors in the membrane of embryonic muscle cell
Lateral electrophoresis and diffusion of Concanavalin A receptors in the membrane of embryonic muscle cell
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胚胎肌细胞膜中伴刀豆球蛋白A受体的横向电泳和扩散
DOI：
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发表时间：
1978
影响因子：
7.8
通讯作者：
James W. Lam
中科院分区：
文献类型：
--
作者：
Mu;WEN;James W. Lam
在胚胎蟾蜍爪蟾肌肉细胞表面施加 10 V/cm 的均匀电场，导致刀豆蛋白 A (Con A) 受体在 10 分钟内向细胞一侧不对称积累，如后场荧光 Con A 标记所示。该场在这些 20 微米宽的细胞上产生 20 mV 的细胞外电压差。该效应在两个方面是可逆的：(a) 将细胞额外暴露于相反极性的同一场 10 分钟，可完全逆转细胞另一侧的不对称积累。 (b) 去除场后发生松弛，并导致 30 分钟内完全恢复均匀分布。积累和恢复运动均独立于细胞代谢，并且本质上表现为电泳和扩散。本方法诱导可检测累积所需的阈值场在1.0至1.5V/cm之间（对应于20微米宽的电池上2-3mV的电压差）。流动性最强的非配体Con A 受体群体的电泳迁移率估计约为2 x 10(-3) 微米/秒/V/cm，而其扩散系数在4-7 x 10(-10) cm2/s 范围内。电场导致 Con A 受体的广泛积累，导致形成不动的聚集体。 Con A 受体似乎由异质的膜成分群体组成，这些成分的电荷特性、迁移率和形成聚集体的能力不同。
A uniform electric field of 10 V/cm applied across the surface of embryonic toad Xenopus muscle cells results in the asymmetric accumulation of concanavalin A (Con A) receptors toward one side of the cells within 10 min, as visualized by postfield fluorescent Con A labeling. This field produces an extracellular voltage difference of 20 mV across these 20-microns wide cells. The effect is reversible in two respects: (a) Additional exposure of the cell to the same field of opposite polarity for 10 min completely reverses the asymmetric accumulation to the other side of the cell. (b) Relaxation occurs after the removal of the field and results in complete recovery of the uniform distribution in 30 min. Both the accumulation and the recovery movements are independent of cell metabolism, and appear to be electrophoretic and diffusional in nature. The threshold field required to induce a detectable accumulation by the present method is between 1.0 and 1.5 V/cm (corresponding to a voltage difference of 2-3 mV across a 20-microns wide cell). The electrophoretic mobility of the most mobile population of nonliganded Con A receptors is estimated to be about 2 x 10(-3) microns/s per V/cm, while their diffusion coefficient is in the range of 4-7 x 10(-10) cm2/s. Extensive accumulation of the Con A receptors by an electric field results in the formation of immobile aggregates. The Con A receptors appear to consist of a heterogeneous population of membrane components different in their charge properties, mobility, and capability in forming aggregates.