Department of Surgery, Research Laboratories, Leipzig University, Leipzig, Germany.
Core Unit Peptide-Technologies, Leipzig University, Leipzig, Germany.
Cell Rep. 2018 Aug 21;24(8):1986-1995. doi: 10.1016/j.celrep.2018.07.071.
Cells respond to mechanical stimuli with altered signaling networks. Here, we show that mechanical forces rapidly induce phosphorylation of CD97/ADGRE5 (pCD97) at its intracellular C-terminal PDZ-binding motif (PBM). Biochemically, this phosphorylation disrupts CD97 binding to PDZ domains of the scaffold protein DLG1. In shear-stressed cells, pCD97 appears not only in junctions, retracting fibers, and the attachment area but also in lost membrane patches, demonstrating (intra)cellular detachment at the CD97 PBM. This motif is critical for the CD97-dependent mechanoresponse. Cells expressing CD97 without the PBM are more deformable, and under shear stress, these cells lose cell contacts faster and show changes in the actin cytoskeleton when compared with cells expressing full-length CD97. Our data indicate CD97 linkage to the cytoskeleton. Consistently, CD97 knockout phenocopies CD97 without the PBM, and membranous CD97 is organized in an F-actin-dependent manner. In summary, CD97 shapes the cellular mechanoresponse through signaling modulation via its PBM.
细胞通过改变信号网络对机械刺激做出反应。在这里，我们表明，机械力迅速诱导 CD97/ADGRE5（pCD97）在其细胞内 PDZ 结合基序（PBM）处发生磷酸化。从生化角度来看，这种磷酸化会破坏 CD97 与支架蛋白 DLG1 的 PDZ 结构域的结合。在受剪切力的细胞中，pCD97 不仅出现在连接处、回缩纤维和附着区域，还出现在丢失的膜斑中，这表明 CD97 PBM 处发生了（细胞内）分离。该基序对于 CD97 依赖性机械反应至关重要。表达没有 PBM 的 CD97 的细胞更具变形性，并且在剪切应力下，与表达全长 CD97 的细胞相比，这些细胞更快地失去细胞接触，并在肌动蛋白细胞骨架中发生变化。我们的数据表明 CD97 与细胞骨架相连。一致地，CD97 敲除与没有 PBM 的 CD97 表现出相同的表型，并且膜性 CD97 以依赖 F-肌动蛋白的方式进行组织。总之，CD97 通过其 PBM 进行信号调节来塑造细胞的机械反应。
