Ca2+ control of actin gelation. Interaction of gelsolin with actin filaments and regulation of actin gelation.
Ca2+ control of actin gelation. Interaction of gelsolin with actin filaments and regulation of actin gelation.
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Ca2 控制肌动蛋白凝胶。
DOI：
10.1016/s0021-9258(19)70590-0
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
T. Stossel
中科院分区：
文献类型：
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作者：
H. Yin;K. Zaner;T. Stossel
我们阐明了肺巨噬细胞的钙依赖性调节蛋白凝溶胶蛋白控制肌动蛋白丝网络结构的机制。在微摩尔Ca ~（2+）存在下，凝溶胶蛋白与Ca ~（2+）结合。的Ca 2 +-凝溶胶蛋白复合物的F-肌动蛋白和肌动蛋白丝的长度在电子显微镜下观察到的表观粘度和流动双折射降低。然而，凝溶胶蛋白浓度引起这些变化并没有影响成比例的变化，在浊度的肌动蛋白丝的解决方案或nonsedimentable肌动蛋白的量，通过放射性测定。从这些发现，我们得出结论，凝溶胶蛋白缩短肌动蛋白丝没有净解聚。这种对肌动蛋白丝长度分布的影响导致预测，低浓度的凝溶胶蛋白将增加肌动蛋白结合蛋白的临界浓度所需的初始凝胶化的肌动蛋白丝在Ca 2+的存在下，提供了一个有效的机制，用于控制肌动蛋白网络结构。我们通过实验验证了这一预测，我们估计Ca 2 +-凝溶胶蛋白复合物有效地打破了化学计量比为1：1的细丝中肌动蛋白单体之间的键。Ca 2 +-凝溶胶蛋白复合物对肌动蛋白溶胶化的影响是迅速的，在0 ° C和37 ° C之间与温度无关，并且通过降低游离Ca 2+浓度来逆转。
We elucidated the mechanism by which gelsolin, a Ca2+-dependent regulatory protein from lung macrophages, controls the network structure of actin filaments. In the presence of micromolar Ca2+, gelsolin bound Ca2+. The Ca2+-gelsolin complex reduced the apparent viscosity and flow birefringence of F-actin and the lengths of actin filaments viewed in the electron microscope. However, concentrations of gelsolin causing these alterations did not effect proportionate changes in the turbidity of actin filament solutions or in the quantity of nonsedimentable actin as determined by a radioassay. From these findings, we conclude that gelsolin shortens actin filaments without net depolymerization. Such an effect on the distribution of actin filament lengths led to the prediction that low concentrations of gelsolin would increase the critical concentration of actin-binding protein required for incipient gelation of actin filaments in the presence of Ca2+, providing an efficient mechanism for controlling actin network structure. We verified the prediction experimentally, and we estimated that the Ca2+-gelsolin complex effectively breaks the bond between actin monomers in filaments with a stoichiometry of 1:1. The effect of Ca2+-gelsolin complex on actin solation was rapid, independent of temperature between 0 degrees and 37 degrees C, and reversed by reducing the free Ca2+ concentration.