Wang D H, Berry K, Howard T H
Department of Cell Biology, University of Alabama, Birmingham School of Medicine.
Cell Motil Cytoskeleton. 1990;16(1):80-7. doi: 10.1002/cm.970160110.
Definition of the kinetics of ligand-activated actin polymerization in the neutrophil is important for ultimately understanding the mechanisms utilized for regulation of actin polymerization in this non-muscle cell. To better define the kinetics of formyl peptide (fMLP)-induced actin polymerization in neutrophils we determined F-actin content at 5 second intervals after activation of human neutrophils with a range (10(-11)-10(-9) M) of fMLP concentrations. The state of actin polymerization was monitored by quantifying F-actin content with NBD phallacidin binding in both flow cytometric and extraction assays. Results demonstrate three successive kinetic periods of fMLP-induced actin polymerization in neutrophils, a lag period, a 5 second period when rate of polymerization is maximal, and a period of declining rate of actin polymerization as F-actin content approaches a maximum. The duration of the lag period, the maximum rate of polymerization, and the maximum extent of polymerization all depend upon the fMLP concentration. The lag period varies from 0 to 12 seconds and is followed in 5-10 seconds by a 5 second burst of actin polymerization when the rate is as great as 9% increase in F-actin content per second. After the 5 second burst of polymerization, the rate of polymerization rapidly declines. The study defines three distinct kinetic periods of fMLP-induced actin polymerization during which important rate-limiting biochemical events occur. The mechanistic and motile implications of kinetic periods are discussed.
定义中性粒细胞中配体激活的肌动蛋白聚合动力学，对于最终理解这种非肌肉细胞中调节肌动蛋白聚合的机制至关重要。为了更好地定义甲酰肽（fMLP）诱导的中性粒细胞肌动蛋白聚合动力学，我们在用一系列（10^(-11)-10^(-9) M）fMLP浓度激活人中性粒细胞后，每隔5秒测定F-肌动蛋白含量。通过在流式细胞术和提取试验中用NBD鬼笔环肽结合定量F-肌动蛋白含量，监测肌动蛋白聚合状态。结果表明，fMLP诱导的中性粒细胞肌动蛋白聚合有三个连续的动力学阶段：一个延迟期、一个聚合速率最大的5秒阶段，以及一个随着F-肌动蛋白含量接近最大值而肌动蛋白聚合速率下降的阶段。延迟期的持续时间、最大聚合速率和最大聚合程度均取决于fMLP浓度。延迟期从0到12秒不等，随后在5-10秒内出现5秒的肌动蛋白聚合爆发，此时速率高达每秒F-肌动蛋白含量增加9%。在5秒的聚合爆发后，聚合速率迅速下降。该研究定义了fMLP诱导的肌动蛋白聚合的三个不同动力学阶段，在此期间发生重要的限速生化事件。讨论了动力学阶段的机制和运动学意义。
