Actin polymerization and interaction with other proteins in temperature-induced gelation of sea urchin egg extracts.
Actin polymerization and interaction with other proteins in temperature-induced gelation of sea urchin egg extracts.
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DOI：
10.1083/jcb.71.3.704
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发表时间：
1976-12
期刊：
影响因子：
--
通讯作者：
Kane RE
中科院分区：
文献类型：
--
作者：
Kane RE
海胆卵细胞质蛋白提取液加热时形成的凝胶被分成两个组分，一个含有F-肌动蛋白，另一个含有58000和22000摩尔重量的两种蛋白质。当在0.1MKCl中结合时，即使在0℃下，这些组分也会形成与加热提取液相同的凝胶物质。这种凝胶是由侧向聚集的F-肌动蛋白细丝组成的网络，这些F-肌动蛋白细丝已登记在案，并显示出另外两种蛋白质存在时产生的复杂的交叉条带模式。低浓度的钙阻止这些蛋白质的组装形成这种复杂的结构，这可能在细胞质中发挥一些细胞骨架的作用。这种F-肌动蛋白与其他蛋白质结合形成凝胶的过程很可能是加热提取物中发生的这一过程的最后一步。在低温下，提取物的凝胶化受到F-肌动蛋白相对缺乏的限制，这表现在100000克时不能沉淀，以及如果将外源F-肌动蛋白添加到冷萃取物中，就会立即凝胶化。提取物中的G-肌动蛋白向F型的转化在低温下明显受到抑制。添加的G-肌动蛋白在萃取物存在的情况下不能在低温下聚合，这直接说明了这一点。这些观察结果与已报道的阿米巴细胞制剂相似，可能在肌动蛋白和这些其他蛋白质参与细胞分裂和后来的发育过程中具有重要意义。
The gel which forms on warming the extracts of the cytoplasmic proteins of sea urchin eggs has been separated into two fractions, one containing F-actin and the other containing two proteins of 58,000 and 22,000 mol wt. When combined in 0.1 M KCl, even at 0 degrees C, these components will form gel material identical to that formed by warming extracts. This gel is a network of laterally aggregated F-actin filaments which are in register and which display a complex cross- banding pattern generated by the presence of the other two proteins. Low concentrations of calcium block the assembly of these proteins to form this complex structure, which may play some cytoskeletal role in the cytoplasm. This association of F-actin with the other proteins to form a gel is very likely the last step fo the process occurring in warmed extracts. At low temperatures, gelation of extracts is limited by the relative absence of F-actin, as demonstrated by the inability to sediment it at 100,000 g and also by the fact that gelation occurs immediately if exogenous F-actin is added to cold extracts. The transformation of the G-actin present in the extract to the F-form is apparently repressed at low temperatures. This is shown directly by the failure of added G-actin to polymerize at low temperatures in the presence of extract. These observations resemble those which have been reported on preparations from amoeboid cells and may be significant in the involvement of actin and these other proteins in cell division and later developmental processes.