Sprouty proteins are in vivo targets of Corkscrew/SHP-2 tyrosine phosphatases
Sprouty proteins are in vivo targets of Corkscrew/SHP-2 tyrosine phosphatases
复制标题
DOI：
10.1242/dev.02255
复制
发表时间：
2006-03-15
期刊：
影响因子：
4.6
通讯作者：
Smith-Bolton, RK
中科院分区：
文献类型：
--
作者：
Jarvis, LA;Toering, SJ;Smith-Bolton, RK
果蝇Corkscrew蛋白及其脊椎动物同源蛋白SHP-2（现在称为Ptpn11）在发育过程中正调节受体酪氨酸激酶（RTK）信号传导，但这些酪氨酸磷酸酶如何促进酪氨酸激酶信号传导尚不清楚。发芽蛋白是酪氨酸磷酸化的RTK反馈抑制剂，但其调控和作用机制也知之甚少。在这里，我们发现Corkscrew/SHP-2蛋白控制着Sprouty的磷酸化和功能。遗传实验表明，Corkscrew/SHP-2和Sprouty蛋白对RTK介导的果蝇发育事件和培养的哺乳动物细胞中的RTK信号传导过程具有相反的作用，并且这些基因表现出剂量敏感的遗传相互作用。在培养细胞中，SHP-2的失活增加了对Sprouty 1关键酪氨酸的磷酸化。在培养细胞和体外，SHP-2以复合物形式与Sprouty 1结合，纯化的SHP-2蛋白使Sprouty 1的关键酪氨酸去磷酸化。在培养的果蝇细胞和发育中的眼睛中，底物诱捕形式的软木塞螺结合了发芽。这些结果确定了Sprouty蛋白是Corkscrew/SHP-2酪氨酸磷酸酶的体内靶点，并显示了Corkscrew/SHP-2蛋白如何通过失活反馈抑制剂来促进RTK信号传导。我们提出这种双负反馈电路塑造了RTK信号事件的输出轮廓。
Drosophila Corkscrew protein and its vertebrate ortholog SHP-2 (now known as Ptpn11) positively modulate receptor tyrosine kinase (RTK) signaling during development, but how these tyrosine phosphatases promote tyrosine kinase signaling is not well understood. Sprouty proteins are tyrosine-phosphorylated RTK feedback inhibitors, but their regulation and mechanism of action are also poorly understood. Here, we show that Corkscrew/SHP-2 proteins control Sprouty phosphorylation and function. Genetic experiments demonstrate that Corkscrew/SHP-2 and Sprouty proteins have opposite effects on RTK-mediated developmental events in Drosophila and an RTK signaling process in cultured mammalian cells, and the genes display dose-sensitive genetic interactions. In cultured cells, inactivation of SHP-2 increases phosphorylation on the critical tyrosine of Sprouty 1. SHP-2 associates in a complex with Sprouty 1 in cultured cells and in vitro, and a purified SHP-2 protein dephosphorylates the critical tyrosine of Sprouty 1. Substrate-trapping forms of Corkscrew bind Sprouty in cultured Drosophila cells and the developing eye. These results identify Sprouty proteins as in vivo targets of Corkscrew/SHP-2 tyrosine phosphatases and show how Corkscrew/SHP-2 proteins can promote RTK signaling by inactivating a feedback inhibitor. We propose that this double-negative feedback circuit shapes the output profile of RTK signaling events.