Ca2+-dependent myosin II activation is required for uropod retraction during neutrophil migration.
Ca2+-dependent myosin II activation is required for uropod retraction during neutrophil migration.
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发表时间：
2000-04
影响因子：
4
通讯作者：
Robert J. Eddy;L. Pierini;Fumio Matsumura;Frederick R. Maxfield
中科院分区：
文献类型：
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作者：
Robert J. Eddy;L. Pierini;Fumio Matsumura;Frederick R. Maxfield
人中性粒细胞内Ca 2+瞬变的缓冲导致由于纤连蛋白和玻连蛋白包被的表面上有缺陷的尾足脱离而降低的运动性。由于[Ca 2 +]i升高的一个潜在目标是肌球蛋白II的激活，我们表征了肌球蛋白II在运动过程中的作用。用肌球蛋白抑制剂（2，3-丁二酮单肟）或肌球蛋白轻链激酶抑制剂（ML-7，ML-9或KT 5926）治疗中性粒细胞导致尾足收缩受损，并在用N-甲酰-Met-Leu-Phe（fMLP）刺激后剂量依赖性地减少趋化作用。用ML-9处理导致F-肌动蛋白和talin重新分布到非收缩的尾足动物，模仿在[Ca 2 +]i缓冲期间观察到的重新分布。受损的尾足收缩和重新分配的F-肌动蛋白和talin肌球蛋白II抑制只观察到的粘合剂基板，如纤连蛋白，而不是粘合性差的基板，如人血清涂层玻璃。在较高浓度的ML-9，细胞极化受到抑制，伪足延伸发生放射状。使用丝氨酸19-磷酸化的肌球蛋白II的调节轻链的特异性抗体，激活的肌球蛋白II的区域被发现在前缘，以及在运动的fMLP刺激的细胞的尾足。[Ca2+]i耗竭导致丝氨酸19-磷酸化肌球蛋白II的水平降低50%，这表明肌球蛋白II通过细胞内Ca 2+瞬变的激活可能是建立极化伪足和在粘附表面上的PMN运动期间提供尾足收缩所需的力的重要步骤。
Buffering of intracellular Ca2+ transients in human neutrophils leads to reduced motility due to defective uropod detachment on fibronectin and vitronectin-coated surfaces. Since one potential target of a rise in [Ca2+]i is the activation of myosin II, we characterized the role of myosin II during motility. Treatment of neutrophils with a myosin inhibitor (2,3-butanedione monoxime), or myosin light chain kinase inhibitors (ML-7, ML-9, or KT5926) resulted in impaired uropod retraction and a dose-dependent decrease in chemokinesis following stimulation with N-formyl-Met-Leu-Phe (fMLP). Treatment with ML-9 resulted in a redistribution of F-actin and talin to the non-retracted uropods, mimicking the redistribution observed during [Ca2+]i buffering. Impairment of uropod retraction and redistribution of F-actin and talin by myosin II inhibition was only observed on adhesive substrates such as fibronectin and not on poorly adhesive substrates such as human serum-coated glass. At higher concentrations of ML-9, cell polarization was inhibited and pseudopod extension occurred radially. Using an antibody specific for serine 19-phosphorylated regulatory light chain of myosin II, regions of activated myosin II were found at the leading edge as well as the uropod in motile fMLP-stimulated cells. [Ca2+]i depletion caused a 50% decrease in the level of serine 19-phosphorylated myosin II suggesting that activation of myosin II by intracellular Ca2+ transients may be an essential step in establishing a polarized pseudopod and providing the force required for uropod retraction during PMN motility on adhesive surfaces.