EGF receptor regulation of cell motility: EGF induces disassembly of focal adhesions independently of the motility-associated PLCgamma signaling pathway.
EGF receptor regulation of cell motility: EGF induces disassembly of focal adhesions independently of the motility-associated PLCgamma signaling pathway.
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发表时间：
1998-03
影响因子：
4
通讯作者：
Heng Xie;M. Pallero;K. Gupta;Philip Chang;Margaret F. Ware;W. Witke;D. Kwiatkowski;D. Lauffenburger;J. Murphy-Ullrich;A. Wells
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文献类型：
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作者：
Heng Xie;M. Pallero;K. Gupta;Philip Chang;Margaret F. Ware;W. Witke;D. Kwiatkowski;D. Lauffenburger;J. Murphy-Ullrich;A. Wells
生长因子诱导的细胞运动性的当前模型引起细胞运动性所需的多种生物物理过程的整合，包括细胞/基质附着的动态形成和破坏沿着膜突起的延伸。为了确定这些生物物理事件是如何通过生物化学信号通路驱动的，我们在这里研究表皮生长因子（EGF）是否诱导成纤维细胞中的粘着斑破坏。我们发现，表皮生长因子治疗NR 6成纤维细胞提出全长野生型表皮生长因子受体（EGFR）减少分数的细胞呈现局灶性粘连从约60%至约30%，在10分钟内。粘着斑解体的剂量依赖性反映了EGF增强的细胞运动性，在0.1 nM EGF下观察到。EGFR激酶活性是必需的，因为表达两种激酶缺陷型EGFR构建体的细胞在EGF存在下保留其粘着斑。局部粘连的短期（30分钟）解体反映在EGF处理的细胞对基质的粘附减少。我们进一步研究了已知的运动相关途径，以确定这些途径是否有助于EGF诱导的效应。我们以前已经证明，磷脂酶C（γ）（PLC γ）激活和动员凝溶胶蛋白从质膜结合状态所需的EGFR介导的细胞运动。相反，我们发现，短期的局部粘连解体是由信号限制性截短的EGFR（c '973）诱导的，它不能激活PLC γ或动员凝溶胶蛋白。PLC抑制剂U 73122对此过程没有影响，也不是所需的肌动蛋白切割能力的凝溶胶蛋白作为EGF治疗减少粘着斑缺乏成纤维细胞，进一步支持的论点，即粘着斑解体是由一个信号的途径不同，涉及PLC γ。因为WT和c '973 EGFR都激活erk MAP激酶通路，我们在此额外探索了这种信号通路，以前与生长因子诱导的细胞运动无关。阻断EGF诱导的有丝分裂和MAP激酶磷酸化的MEK抑制剂PD 98059的水平也消除EGF诱导的粘着斑解体和细胞运动性。总之，我们首次表征了EGFR激酶活性直接刺激粘着斑分解和细胞/基质脱离的能力，与其刺激迁移的能力有关。此外，我们提出了一个模型，EGF诱导的运动细胞反应，其中PLC γ途径刺激细胞运动是不同的MAP激酶依赖的信号通路导致拆卸和重组的细胞基质粘附。
A current model of growth factor-induced cell motility invokes integration of diverse biophysical processes required for cell motility, including dynamic formation and disruption of cell/substratum attachments along with extension of membrane protrusions. To define how these biophysical events are actuated by biochemical signaling pathways, we investigate here whether epidermal growth factor (EGF) induces disruption of focal adhesions in fibroblasts. We find that EGF treatment of NR6 fibroblasts presenting full-length WT EGF receptors (EGFR) reduces the fraction of cells presenting focal adhesions from approximately 60% to approximately 30% within 10 minutes. The dose dependency of focal adhesion disassembly mirrors that for EGF-enhanced cell motility, being noted at 0.1 nM EGF. EGFR kinase activity is required as cells expressing two kinase-defective EGFR constructs retain their focal adhesions in the presence of EGF. The short-term (30 minutes) disassembly of focal adhesions is reflected in decreased adhesiveness of EGF-treated cells to substratum. We further examine here known motility-associated pathways to determine whether these contribute to EGF-induced effects. We have previously demonstrated that phospholipase C(gamma) (PLCgamma) activation and mobilization of gelsolin from a plasma membrane-bound state are required for EGFR-mediated cell motility. In contrast, we find here that short-term focal adhesion disassembly is induced by a signaling-restricted truncated EGFR (c'973) which fails to activate PLCgamma or mobilize gelsolin. The PLC inhibitor U73122 has no effect on this process, nor is the actin severing capacity of gelsolin required as EGF treatment reduces focal adhesions in gelsolin-devoid fibroblasts, further supporting the contention that focal adhesion disassembly is signaled by a pathway distinct from that involving PLCgamma. Because both WT and c'973 EGFR activate the erk MAP kinase pathway, we additionally explore here this signaling pathway, not previously associated with growth factor-induced cell motility. Levels of the MEK inhibitor PD98059 that block EGF-induced mitogenesis and MAP kinase phosphorylation also abrogate EGF-induced focal adhesion disassembly and cell motility. In summary, we characterize for the first time the ability of EGFR kinase activity to directly stimulate focal adhesion disassembly and cell/substratum detachment, in relation to its ability to stimulate migration. Furthermore, we propose a model of EGF-induced motogenic cell responses in which the PLCgamma pathway stimulating cell motility is distinct from the MAP kinase-dependent signaling pathway leading to disassembly and reorganization of cell-substratum adhesion.