ARHGAP18, a GTPase-activating protein for RhoA, controls cell shape, spreading, and motility.
ARHGAP18, a GTPase-activating protein for RhoA, controls cell shape, spreading, and motility.
复制标题
DOI：
10.1091/mbc.e11-04-0364
复制
发表时间：
2011-10
影响因子：
3.3
通讯作者：
Senga T
中科院分区：
文献类型：
--
作者：
Maeda M;Hasegawa H;Hyodo T;Ito S;Asano E;Yuang H;Funasaka K;Shimokata K;Hasegawa Y;Hamaguchi M;Senga T
使用siRNA文库，我们发现ARHGAP 18对于肌动蛋白应力纤维和粘着斑的组织是必不可少的。ARHGAP 18是调节RhoA以控制细胞运动和扩散的关键因子之一。Rho GTP酶是响应细胞外刺激而传递生化信号以引起肌动蛋白细胞骨架变化的分子开关。Rho GTP酶在活性的GTP结合状态和非活性的GDP结合状态之间循环。这些状态由两个不同的蛋白质家族-鸟嘌呤核苷酸交换因子和GTP酶激活蛋白（GAP）调节。我们研究了以前未表征的GAP，ARHGAP 18（MacGAP）的作用。ARHGAP 18的过表达抑制了RhoA的活性并破坏了应力纤维的形成。相反，沉默ARHGAP 18的小干扰RNA转染增强应力纤维的形成和诱导细胞变圆。我们研究了ARHGAP 18在细胞扩散和迁移中的作用。免疫荧光分析显示，ARHGAP 18定位于细胞扩散和迁移过程中的前缘。ARHGAP 18敲除细胞表现出受损的扩展，过早形成应力纤维，并持续激活RhoA细胞附着。此外，ARHGAP 18的敲低和过表达分别导致细胞迁移的抑制和促进。此外，ARHGAP 18是细胞迁移极化所必需的。我们的研究结果将ARHGAP 18定义为调节RhoA以控制细胞形状、扩散和迁移的关键因素之一。
Using a library of siRNAs, we found that ARHGAP18 was essential for the organization of actin stress fibers and focal adhesion. ARHGAP18 is one of the crucial factors for the regulation of RhoA in order to control cell motility and spreading. Rho GTPases are molecular switches that transmit biochemical signals in response to extracellular stimuli to elicit changes in the actin cytoskeleton. Rho GTPases cycle between an active, GTP-bound state and an inactive, GDP-bound state. These states are regulated by two distinct families of proteins—guanine nucleotide exchange factors and GTPase-activating proteins (GAPs). We studied the role of a previously uncharacterized GAP, ARHGAP18 (MacGAP). Overexpression of ARHGAP18 suppressed the activity of RhoA and disrupted stress fiber formation. Conversely, silencing of ARHGAP18 by small interfering RNA transfection–enhanced stress fiber formation and induced rounding of cells. We examined the role of ARHGAP18 in cell spreading and migration. Immunofluorescence analysis revealed that ARHGAP18 was localized to the leading edge during cell spreading and migration. ARHGAP18-knockdown cells showed impaired spreading, premature formation of stress fibers, and sustained activation of RhoA upon cell attachment. In addition, knockdown and overexpression of ARHGAP18 resulted in the inhibition and promotion of cell migration, respectively. Furthermore, ARHGAP18 was required for the polarization of cells for migration. Our results define ARHGAP18 as one of the crucial factors for the regulation of RhoA for the control of cell shape, spreading, and migration.