Early molecular events in the assembly of matrix adhesions at the leading edge of migrating cells
Early molecular events in the assembly of matrix adhesions at the leading edge of migrating cells
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DOI：
10.1242/jcs.00792
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发表时间：
2003-11-15
影响因子：
4
通讯作者：
Geiger, B
中科院分区：
文献类型：
--
作者：
Zaidel-Bar, R;Ballestrem, C;Geiger, B
细胞运动是由前缘的突出、新基质粘附的形成和后缘的缩回的重复循环驱动的。在这项研究中，我们解决了分子组成和动力学的局灶性复合物，下形成的运动细胞的领导lampheres，和他们的成熟成局灶性粘连。我们结合相衬和荧光显微镜的方法来监测磷酸酪氨酸和九种不同的粘着斑蛋白的掺入到内皮细胞的焦点复合物中，迁移到体外“伤口”。我们发现，新形成的复合物位于后面的肌动蛋白，VASP和α-辅肌动蛋白丰富的区域在lammelipodium。它们是高度酪氨酸磷酸化的，含有β（3）-整联蛋白、talin、桩蛋白和低水平的粘着斑蛋白和FAK，但显然缺乏zyxin和张力蛋白。这些蛋白质被募集到焦点复合物中是顺序发生的，因此它们的特定蛋白质组成取决于它们的年龄。有趣的是，双色，延时电影可视化桩蛋白和zyxin，表明从富桩蛋白的局灶性复合物的过渡到明确的，含zyxin的局灶性粘连，只有在前缘停止前进或缩回。这些观察照亮，第一次，在焦点复合体组装的早期阶段和动态过程与其转化为焦点粘合。
Cellular locomotion is driven by repeated cycles of protrusion of the leading edge, formation of new matrix adhesions and retraction of the trailing edge. In this study we addressed the molecular composition and dynamics of focal complexes, formed under the leading lamellae of motile cells, and their maturation into focal adhesions. We combined phase-contrast and fluorescence microscopy approaches to monitor the incorporation of phosphotyrosine and nine different focal adhesion proteins into focal complexes in endothelial cells, migrating into an in vitro 'wound'. We show that newly formed complexes are located posterior to an actin-, VASP- and alpha-actinin-rich region in the lammelipodium. They are highly tyrosine phosphorylated, contain beta(3)-integrin, talin, paxillin and low levels of vinculin and FAK, but are apparently devoid of zyxin and tensin. The recruitment of these proteins into focal complexes occurs sequentially, so that their specific protein composition depends on their age. Interestingly, double color, time-lapse movies visualizing both paxillin and zyxin, indicated that the transition from paxillin-rich focal complexes to definitive, zyxin-containing focal adhesions, takes place only after the leading edge stops advancing or retracts. These observations illuminate, for the first time, early stages in focal complex assembly and the dynamic process associated with its transformation into focal adhesion.