Epidermal growth factor stimulation of the ACK1/Dbl pathway in a Cdc42 and Grb2-dependent manner
Epidermal growth factor stimulation of the ACK1/Dbl pathway in a Cdc42 and Grb2-dependent manner
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DOI：
10.1006/bbrc.2001.5004
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发表时间：
2001-06-08
影响因子：
3.1
通讯作者：
Satoh, T
中科院分区：
文献类型：
--
作者：
Kato-Stankiewicz, J;Ueda, S;Satoh, T
酪氨酸激酶 ACK1 磷酸化并激活鸟嘌呤核苷酸交换因子 Dbl，进而指导 Rho 家族 GTP 结合蛋白。然而，ACK1/Dbl 信号响应细胞外刺激的调节机制仍然知之甚少。在这里，我们描述了表皮生长因子刺激 ACK1/Dbl 通路，导致肌动蛋白细胞骨架重排。分别通过 Cdc4a/Rac 相互作用结合域和显性失活 Grb2 突变体的过表达来评估两种 ACK1 结合蛋白 Cdc42 和 Grb2 的作用。通过使用这些构建体特异性抑制ACK1与Cdc42或Grb2的相互作用，减少了响应EG;F的ACK1和Dbl的酪氨酸磷酸化。因此，ACK1 的激活和随后的下游信号传导需要细胞内 Cdc42 依赖性和 Grb2 依赖性过程。此外，我们还发现，当ACK1异位表达时，EC;F会短暂地诱导局灶复合体和应力纤维的形成。这些结构的诱导对来自肉毒梭菌的肉毒毒素 C 的作用完全敏感，表明 Rho 的关键作用。这些结果提供了证据，证明 ACK1 通过磷酸化和 Dbl 等 GEF 的激活，充当 Rho 家族 GTP 结合蛋白的 EGF 信号介体。 (C) 2001 年学术出版社。
The tyrosine kinase ACK1 phosphorylates and activates the guanine nucleotide exchange factor Dbl, which in turn directs the Rho family GTP-binding proteins. However, the regulatory mechanism of ACK1/Dbl signaling in response to extracellular stimuli remains poorly understood. Here we describe that epidermal growth factor stimulates the ACK1/Dbl pathway, leading to actin cytoskeletal rearrangements. The role of the two ACK1-binding proteins Cdc42 and Grb2 was assessed by overexpression of the Cdc4a/Rac interactive binding domain and dominant-negative Grb2 mutant, respectively. Specific inhibition of the interaction of ACK1 with Cdc42 or Grb2 by the use of these constructs diminished tyrosine phosphorylation of both ACK1 and Dbl in response to EG;F. Therefore, the activation of ACK1 and subsequent downstream signaling require both Cdc42-dependent and Grb2-dependent processes within the cell. In addition, we show that EC;F transiently in duces formation of the focal complex and stress fibers when ACK1 was ectopically expressed. The induction of these structures was totally sensitive to the action of botulinum toxin C from Clostridium botulinum, suggesting a pivotal role of Rho. These results provide evidence that ACK1 acts as a mediator of EGF signals to Rho family GTP-binding proteins through phosphorylation and activation of GEFs such as Dbl. (C) 2001 Academic Press.