Martin Karen H, Boerner Scott A, Parsons J Thomas
Department of Microbiology, University of Virginia Health System, Charlottesville, Virginia 22908, USA.
Cell Motil Cytoskeleton. 2002 Feb;51(2):76-88. doi: 10.1002/cm.10018.
Focal adhesion kinase (FAK) is a regulator of numerous adhesion-dependent processes including cell migration, cell proliferation, and cell survival. The C-terminal domain of FAK, FAK-related nonkinase (FRNK), is autonomously expressed and functions as an inhibitor of FAK signaling. Previous attempts to use FRNK as a tool to dissect FAK signaling have been limited because of an inability to temporally regulate the inhibitory functions of FRNK. In this report, we describe and characterize a conditionally targeted form of FRNK that was created by fusing the hormone-binding domain of the estrogen receptor (ER*) to the C-terminus of FRNK. In the absence of added hormone, FRNK-ER* was diffusely distributed throughout the cytoplasm of cells. Upon addition of hormone, the cytoplasmic pool of FRNK-ER* was rapidly redistributed to focal adhesions. We demonstrate that cells expressing FRNK-ER* show a hormone-dependent decrease in FAK tyrosine phosphorylation and cell migration. Furthermore, when cells expressing of FRNK-ER* were treated with hormone, the cells responded with a dramatic change in cell morphology, suggesting a role for FAK in the regulation of the adhesive properties of focal adhesions.
粘着斑激酶（FAK）是众多依赖粘着的过程的调节因子，这些过程包括细胞迁移、细胞增殖和细胞存活。FAK的C末端结构域，即FAK相关非激酶（FRNK），可自主表达并作为FAK信号传导的抑制剂发挥作用。以往将FRNK用作剖析FAK信号传导工具的尝试受到限制，因为无法在时间上调节FRNK的抑制功能。在本报告中，我们描述并表征了一种条件性靶向形式的FRNK，它是通过将雌激素受体（ER*）的激素结合结构域融合到FRNK的C末端而构建的。在未添加激素的情况下，FRNK-ER在细胞的整个细胞质中呈弥散分布。加入激素后，FRNK-ER的细胞质池迅速重新分布到粘着斑。我们证明，表达FRNK-ER的细胞显示出激素依赖性的FAK酪氨酸磷酸化和细胞迁移减少。此外，当用激素处理表达FRNK-ER的细胞时，细胞的形态会发生显著变化，这表明FAK在调节粘着斑的粘着特性中发挥作用。
