Sprouty Proteins Inhibit Receptor-mediated Activation of Phosphatidylinositol-specific Phospholipase C
Sprouty Proteins Inhibit Receptor-mediated Activation of Phosphatidylinositol-specific Phospholipase C
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DOI：
10.1091/mbc.e10-02-0123
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发表时间：
2010-10-01
影响因子：
3.3
通讯作者：
Licht, Jonathan D.
中科院分区：
文献类型：
--
作者：
Akbulut, Simge;Reddi, Alagarsamy L.;Licht, Jonathan D.
Sprouty(Spry)蛋白是受体酪氨酸激酶信号的负调节因子；然而，它们的确切作用机制仍不完全清楚。我们鉴定了磷脂酰肌醇特异的磷脂酶C(PLC)-γ是Spry1和SPRY2蛋白的合作伙伴。SPRY-PLC伽马相互作用依赖于PLC伽马的Src同源2结构域以及Spry1和SPRY2中保守的N末端酪氨酸残基。Spry1和SPRY2的过表达与PLC-γ磷酸化降低和PLC-γ活性降低有关，通过产生肌醇(1，4，5)-三磷酸(IP3)和二酰甘油来衡量，而Spry1或Spry1、-2和-4缺失的细胞在基线水平显示IP3的产生增加，并对生长因子信号的反应进一步增加。Spry 1或SPRY2的过表达或小干扰RNA介导的PLC Gamma 1或PLC Gamma 2的敲除可抑制钙依赖报告基因的活性，这表明Spry抑制了PLC Gamma下游的钙介导的信号转导。此外，在高度依赖PLCγ活性和钙信号的T细胞中，Spry的过表达抑制了T细胞受体介导的钙释放。因此，来自Spry1基因敲除小鼠的培养的T细胞表现出对T细胞受体刺激的反应增加的增殖。这些数据突显了Spry的一个重要作用，它可能允许这些蛋白质通过多个受体影响信号。
Sprouty (Spry) proteins are negative regulators of receptor tyrosine kinase signaling; however, their exact mechanism of action remains incompletely understood. We identified phosphatidylinositol-specific phospholipase C (PLC)-gamma as a partner of the Spry1 and Spry2 proteins. Spry-PLC gamma interaction was dependent on the Src homology 2 domain of PLC gamma and a conserved N-terminal tyrosine residue in Spry1 and Spry2. Overexpression of Spry1 and Spry2 was associated with decreased PLC gamma phosphorylation and decreased PLC gamma activity as measured by production of inositol (1,4,5)-triphosphate (IP3) and diacylglycerol, whereas cells deficient for Spry1 or Spry1, -2, and -4 showed increased production of IP3 at baseline and further increased in response to growth factor signals. Overexpression of Spry 1 or Spry2 or small-interfering RNA-mediated knockdown of PLC gamma 1 or PLC gamma 2 abrogated the activity of a calcium-dependent reporter gene, suggesting that Spry inhibited calcium-mediated signaling downstream of PLC gamma. Furthermore, Spry overexpression in T-cells, which are highly dependent on PLC gamma activity and calcium signaling, blocked T-cell receptor-mediated calcium release. Accordingly, cultured T-cells from Spry1 gene knockout mice showed increased proliferation in response to T-cell receptor stimulation. These data highlight an important action of Spry, which may allow these proteins to influence signaling through multiple receptors.