Direct observation of α-actinin tension and recruitment at focal adhesions during contact growth.
Direct observation of α-actinin tension and recruitment at focal adhesions during contact growth.
复制标题
直接观察接触生长期间粘着斑处的α-肌动蛋白张力和募集。
DOI：
10.1016/j.yexcr.2014.07.026
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发表时间：
2014
影响因子：
3.7
通讯作者：
Hua,SusanZ
中科院分区：
文献类型：
--
作者：
Ye,Nannan;Verma,Deepika;Meng,Fanjie;Davidson,MichaelW;Suffoletto,Kevin;Hua,SusanZ
粘附细胞与细胞外基质通过细胞-基质接触在粘着灶处相互作用。粘着斑的动态组装和拆卸使得细胞能够附着、迁移和生长。虽然已经广泛观察到机械力对粘着斑形成和生长的影响，但粘着斑复合物中特定蛋白质的力负荷尚不清楚。通过在MDCK细胞中共表达力敏的α-辅肌动蛋白FRET探针和荧光标记的桩蛋白，我们同时观察了细胞迁移过程中α-辅肌动蛋白张力的时间依赖性变化和粘着斑的动态变化。我们发现，在α-辅肌动蛋白的张力增加，在其生长阶段的粘附力的增长相一致。粘着斑的扩大是通过α-辅肌动蛋白和桩蛋白的力敏感性募集到粘着位点。α-辅肌动蛋白张力的变化和α-辅肌动蛋白在主动粘附中的相关重新定位也指导粘附的生长方向。结果支持细胞骨架张力与粘着斑连接蛋白α-辅肌动蛋白偶联的模型。溶血磷脂酸引起α-辅肌动蛋白张力立即增加，随后是剧烈的粘着斑形成和延长。Rho-ROCK抑制剂Y27632的应用导致α-辅肌动蛋白张力的可逆性降低和粘着斑的解离，表明肌球蛋白II介导的收缩力参与粘着斑动力学。这些结果表明，α-辅肌动蛋白不仅作为细胞骨架与整合素之间的物理连接物，而且还参与粘附位点的力传递，促进粘附细胞的生长。
Adherent cells interact with extracellular matrixviacell–substrate contacts at focal adhesions. The dynamic assembly and disassembly of focal adhesions enables cell attachment, migration and growth. While the influence of mechanical forces on the formation and growth of focal adhesions has been widely observed, the force loading on specific proteins at focal adhesion complex is not clear. By co-expressing force sensitive α-actinin FRET probes and fluorescence labeled paxillin in MDCK cells, we have simultaneously observed the time-dependent changes in tension in α-actinin and the dynamics of focal adhesion during cell migration. We show that increase in tension in α-actinin at the focal adhesion coincides with elongation of the adhesion in its growth phase. The enlargement of focal adhesion is through a force sensitive recruitment of α-actinin and paxillin to the adhesion sites. Changes in α-actinin tension and correlated relocation of α-actinin in an active adhesion also guide the growth direction of the adhesion. The results support the model that cytoskeletal tension is coupled to focal adhesionviathe linking protein, α-actinin at the adhesion complex. Lysophosphatidic acid caused an immediate increase in α-actinin tension followed by drastic focal adhesion formation and elongation. Application of Rho-ROCK inhibitor, Y27632, resulted in reversible reduction in tension in α-actinin and disassociation of focal adhesion, suggesting the involvement of myosin-II mediated contractile force in the focal adhesion dynamics. These findings suggest that α-actinin not only serves as a physical linker between cytoskeleton and integrin, but also participates in force transmission at adhesion sites to facilitate adhesion׳s growth.