SUBCELLULAR COMPARTMENTALIZATION BY LOCAL DIFFERENTIATION OF CYTOPLASMIC STRUCTURE
SUBCELLULAR COMPARTMENTALIZATION BY LOCAL DIFFERENTIATION OF CYTOPLASMIC STRUCTURE
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DOI：
10.1002/cm.970100107
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发表时间：
1988-01-01
影响因子：
--
通讯作者：
TAYLOR, DL
中科院分区：
文献类型：
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作者：
LUBYPHELPS, K;TAYLOR, DL
真核细胞通过内膜的区室化和内源性大分子通过特异性结合机制的亚细胞定位是熟悉的概念。在这份报告中，我们提出的证据表明，细胞质的基质，它周围，并包含膜结合的车厢，也可能是由其亚显微结构，排序亚细胞颗粒大小的基础上的局部分化划分。通过比率成像和光漂白后荧光恢复（FRAP）研究了活细胞中尺寸分级的荧光示踪剂颗粒的亚细胞分布。大颗粒和小颗粒在胞质体积内表现出不同的分布，表明大颗粒相对被排除在某些区域之外。虽然这种现象的结构基础尚未详细了解，但大颗粒和小颗粒的比率成像可用作经验工具来识别细胞质隔室以供进一步研究。细胞质扩散系数（Dcyto）和大颗粒的%移动的分数显示出相当大的空间变异超过投影面积的细胞，而Dcyto和%移动的分数的小颗粒没有。一个模型来解释这种差异。基于此模型，提出了一种方法，通过该方法，FRAP可以用于检测活细胞的细胞质基质中的溶胶-凝胶转变。
The compartmentalization of eukaryotic cells by internal membranes and the subcellular localization of endogenous macromolecules by specific binding mechanisms are familiar concepts. In this report we present evidence that the cytoplasmic ground substance, which surrounds and contains the membranebound compartments, may also be compartmentalized by local differentiations of its submicroscopic structure that sort subcellular particles on the basis of size. The subcellular distribution of size‐fractionated, fluorescent tracer particles was studied in living cells by ratio imaging and fluorescence recovery after photobleaching (FRAP). Large and small particles showed different distributions within the cytoplasmic volume, suggesting that the large particles were relatively excluded from some domains. While the structural basis for this phenomenon is not yet understood in detail, ratio imaging of large and small particles can be used as an empirical tool to identify cytoplasmic compartments for further study. The cytoplasmic diffusion coefficient (Dcyto) and % mobile fraction of the large particles showed considerable spatial variation over the projected area of the cell, while Dcytoand % mobile fraction of the small particles did not. A model is presented to account for this difference. Based on this model, a method is proposed by which FRAP can be used to detect sol‐gel transitions in the cytoplasmic ground substance of living cells.