GIT1 is a novel MEK1-ERK1/2 scaffold that localizes to focal adhesions.
GIT1 is a novel MEK1-ERK1/2 scaffold that localizes to focal adhesions.
复制标题
DOI：
10.1042/cbi20090016
复制
发表时间：
2009-12-16
影响因子：
3.9
通讯作者：
Berk BC
中科院分区：
文献类型：
--
作者：
Zhang N;Cai W;Yin G;Nagel DJ;Berk BC
细胞极性对于细胞迁移是至关重要的，并且需要在亚细胞结构域中进行局部信号转导。最近的证据表明，活化ERK 1/2（细胞外信号调节激酶1/2）在局灶性粘连是必不可少的细胞迁移。GIT 1（G蛋白偶联受体激酶相互作用蛋白1）已被证明可以结合桩蛋白并调节局灶性粘附解体。我们以前曾报道，GIT 1结合到MEK 1 [MAPK（丝裂原活化蛋白激酶）/ERK激酶1]，并作为一个支架，以增强ERK 1/2激活响应EGF（表皮生长因子）。在本研究中，我们发现GIT 1与ERK 1/2在局灶性粘连中相关，并且这种相关性在EGF刺激后增加。ERK 1/2的CC（卷曲螺旋）结构域是与GIT 1相关、移位至粘着斑以及细胞扩散和迁移所必需的。免疫荧光染色显示，EGF刺激后，GIT 1与pERK 1/2（磷酸化ERK 1/2）共定位于局灶性粘连。GIT 1和ERK 1/2的结合在功能上是重要的，因为去除缺少CC结构域的ERK 2突变体[ERK 2（del CC）]显著降低了pERK 1/2向粘着斑的移位、EGF诱导的细胞铺展和迁移。总之，ERK 1/2的CC结构域对于结合GIT 1、对于粘着斑中的ERK 1/2活化以及对于细胞扩散和迁移是必需的。
Cell polarity is critical for cell migration and requires localized signal transduction in subcellular domains. Recent evidence demonstrates that activation of ERK1/2 (extracellular-signal-regulated kinase 1/2) in focal adhesions is essential for cell migration. GIT1 (G-protein-coupled receptor kinase-interacting protein 1) has been shown to bind paxillin and regulate focal-adhesion disassembly. We have previously reported that GIT1 binds to MEK1 [MAPK (mitogen-activated protein kinase)/ERK kinase 1] and acts as a scaffold to enhance ERK1/2 activation in response to EGF (epidermal growth factor). In the present study we show that GIT1 associates with ERK1/2 in focal adhesions and this association increases after EGF stimulation. The CC (coiled-coil) domain of ERK1/2 is required for association with GIT1, translocation to focal adhesions, and cell spreading and migration. Immunofluorescent staining showed that, after EGF stimulation, GIT1 co-localized with pERK1/2 (phosphorylated ERK1/2) in focal adhesions. The binding of GIT1 and ERK1/2 was functionally important, since transfecting an ERK2 mutant lacking the CC domain [ERK2(del CC)] significantly decreased pERK1/2 translocation to focal adhesions, cell spreading and migration induced by EGF. In summary, the CC domain of ERK1/2 is necessary for binding to GIT1, for ERK1/2 activation in focal adhesions, and for cell spreading and migration.