Bernstein B W, Bamburg J R
Department of Biochemistry, Colorado State University, Fort Collins 80523.
Neurochem Res. 1987 Oct;12(10):929-35. doi: 10.1007/BF00966315.
Depolarization of mouse brain synaptosomes elicits transmitter release and modifies factors that regulate cytoskeletal actin (C-actin) levels. We previously reported (Bernstein and Bamburg, J. Neurosci. 1985. 5:2565-2569) that depolarization causes a release of about 25% of the actin associated with the cytoskeleton of synaptosomal lysates. From our current studies we conclude that depolarization only transiently perturbs the balance in opposing factors which regulate C-actin levels in lysates. Prolonged incubation of the lysates permits the actin to reequilibrate so that no difference between C-actin levels of resting and depolarized synaptosomes is observed. Both the initial transient release of actin from the cytoskeleton and its reassociation with the cytoskeleton during prolonged incubation are calcium dependent and involve factors in both the cytoskeletal and soluble fractions. Depolarization initiates modifications that both increase and decrease the C-actin level probably through mechanisms involving calcium sensitive actin binding proteins.
小鼠脑突触体的去极化引发递质释放，并改变调节细胞骨架肌动蛋白（C-肌动蛋白）水平的因子。我们之前报道过（伯恩斯坦和班伯格，《神经科学杂志》，1985年。第5卷：2565 - 2569页），去极化会导致约25%与突触体裂解物细胞骨架相关的肌动蛋白释放。从我们目前的研究中我们得出结论，去极化只是短暂地扰乱了调节裂解物中C-肌动蛋白水平的相反因子之间的平衡。裂解物的长时间孵育使肌动蛋白能够重新平衡，因此未观察到静息和去极化突触体的C-肌动蛋白水平之间存在差异。肌动蛋白最初从细胞骨架的短暂释放及其在长时间孵育期间与细胞骨架的重新结合均依赖于钙，并且涉及细胞骨架和可溶性部分中的因子。去极化引发的修饰可能通过涉及钙敏感肌动蛋白结合蛋白的机制，既增加又降低C-肌动蛋白水平。
