Immobilized DLL4-induced Notch signaling is mediated by dynamics of the actin cytoskeleton
Immobilized DLL4-induced Notch signaling is mediated by dynamics of the actin cytoskeleton
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固定化 DLL4 诱导的 Notch 信号传导由肌动蛋白细胞骨架的动力学介导
DOI：
10.1016/j.bbrc.2022.02.084
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发表时间：
2022
影响因子：
3.1
通讯作者：
Itoh Motoyuki
中科院分区：
文献类型：
--
作者：
Handa Hikaru;Idesako Nobuo;Itoh Motoyuki
缺口信号对组织发育和动态平衡是必不可少的，作为癌症治疗、组织工程和再生医学的一个有吸引力的靶点而受到关注。为了激活信号，Notch受体在与其配体结合后经历蛋白质分解。这一过程是由机械拉力介导的，而受体跨内吞作用在提供这一力的过程中起着核心作用。另一方面，固定在载体材料上的Notch配体也可以诱导人工激活Notch。然而，固定化配基蛋白激活信号的机制还不完全清楚。在这里，我们发现Notch1表达细胞中的肌动蛋白细胞骨架参与了DLL4(Delta-like Ligand 4)固定化诱导的信号激活，结果表明，药物抑制肌动蛋白动力学削弱了DLL4包被的微球诱导的Notch信号转导。此外，抑制肌动蛋白动力学显著损害细胞迁移，并与Notch信号活性相关。我们还研究了Notchcis内吞作用(Notch受体内吞进入信号接收细胞)作为肌动蛋白介导的细胞生物学过程的作用，以进一步探讨DLL4包被的微球激活Notch的机制。用动力蛋白抑制剂抑制受体顺式内吞作用不会改变DLL4包被的微球诱导的Notch信号转导，表明信号激活不是由动力蛋白依赖的受体顺式内吞作用介导的。这些发现表明，Notch的激活主要是由基于肌动蛋白的细胞运动驱动的，这可能为受体的切割提供了足够的机械力，但不是通过受体顺式内吞作用。
Notch signaling, which is essential for tissue development and homeostasis, has received attention as an attractive target for cancer therapy, tissue engineering and regenerative medicine. For signal activation, the Notch receptor undergoes proteolysis after binding to its ligand. This process is mediated by a mechanical pulling force, and receptortrans-endocytosis is known to play a central role in supplying the force. On the other hand, Notch ligands immobilized on carrier materials also induce artificial Notch activation. However, the mechanism of signal activation by immobilized ligand proteins is not fully understood. Here, we found that the actin cytoskeleton in Notch1-expressing cells contributes to signal activation induced by immobilized DLL4 (Delta-like ligand 4), and the results showed that pharmacological inhibition of actin dynamics impaired Notch signaling induced by DLL4-coated beads. Moreover, inhibition of actin dynamics remarkably impaired cell migration and was correlated with Notch signaling activity. We also investigated the contribution of Notchcis-endocytosis (the endocytosis of Notch receptor into signal-receiving cells) as an actin-mediated cell biological process to further explore the mechanism of Notch activation by DLL4-coated beads. Compromising the receptorcis-endocytosis pathway with the dynamin inhibitor did not alter DLL4-coated bead-induced Notch signaling, indicating that signal activation is not mediated by dynamin-dependent receptorcis-endocytosis. These findings suggest that Notch activation by immobilized ligands is primarily driven by actin-based cell movement, which might supply a sufficient mechanical force for receptor cleavage, but not by receptorcis-endocytosis.