Queen's University Cancer Research Institute, Division of Cancer Biology and Genetics, Department of Biochemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Cell Signal. 2010 Mar;22(3):427-36. doi: 10.1016/j.cellsig.2009.10.014.
Activation of Kit receptor protein-tyrosine kinase (PTK) by its ligand Stem Cell Factor (SCF) is required for the development of mast cells, and for the regulation of mast cell proliferation, migration and modulation of inflammatory mediator release. Recent studies have implicated the non-receptor PTK Fps/Fes (hereafter referred to as Fes) in signaling downstream of oncogenic Kit, however, the potential role of Fes in regulating Kit signaling is not well defined. In this study, we show that SCF induces transient tyrosine phosphorylation of wild-type Fes as well as kinase-dead Fes in bone marrow-derived mast cells (BMMCs). The latter finding implicates an upstream kinase acting on Fes, which we identified as Fyn PTK. SCF treatment of BMMCs promoted recruitment of Fes to Kit, potentially via direct interaction of the Fes SH2 domain with phosphorylated Kit. While Fes was not required for SCF-induced signaling to Akt and Erk kinases, Fes-deficient (fes-/-) BMMCs displayed a defect in sustained p38 kinase activation, compared to control cells. SCF-treated Fes-deficient BMMCs also displayed elevated beta1 integrin-mediated cell adhesion and spreading on fibronectin, compared to control cells, and a reduction in cell polarization at later times of SCF treatment. Restoring Fes expression in fes-/- BMMCs by retroviral transduction was sufficient to rescue cell spreading and polarization defects. Interestingly, SCF-induced chemotaxis of BMMCs was also defective in Fes-deficient BMMCs, and restored in Fes-rescue BMMCs. Overall, these results implicate Fes in regulating cross-talk between Kit and beta1 integrins to promote cytoskeletal reorganization and motility of mast cells.
Kit 受体蛋白酪氨酸激酶（PTK）的配体干细胞因子（SCF）的激活对于肥大细胞的发育以及调节肥大细胞增殖、迁移和炎症介质释放的调节是必需的。最近的研究表明，非受体 PTK Fps/Fes（以下简称 Fes）参与了致癌 Kit 的信号转导，然而，Fes 在调节 Kit 信号中的潜在作用尚未得到很好的定义。在这项研究中，我们表明 SCF 诱导骨髓来源的肥大细胞（BMMCs）中野生型 Fes 和激酶失活的 Fes 的短暂酪氨酸磷酸化。后一种发现暗示了作用于 Fes 的上游激酶，我们将其鉴定为 Fyn PTK。SCF 处理 BMMC 促进 Fes 向 Kit 的募集，可能是通过 Fes SH2 结构域与磷酸化的 Kit 的直接相互作用。虽然 Fes 不是 SCF 诱导的 Akt 和 Erk 激酶信号所必需的，但与对照细胞相比，Fes 缺陷（fes-/-）BMMC 显示出持续的 p38 激酶激活缺陷。与对照细胞相比，用 SCF 处理的 Fes 缺陷 BMMC 也显示出β1 整合素介导的细胞粘附和在纤维连接蛋白上的扩展增加，并且在 SCF 处理的后期时间点显示出细胞极化减少。通过逆转录病毒转导在 fes-/-BMMC 中恢复 Fes 表达足以挽救细胞扩展和极化缺陷。有趣的是，SCF 诱导的 BMMC 趋化性在 Fes 缺陷 BMMC 中也是有缺陷的，并且在 Fes 挽救 BMMC 中恢复。总体而言，这些结果表明 Fes 参与调节 Kit 和β1 整合素之间的串扰，以促进肥大细胞的细胞骨架重排和运动。
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