Diacylglycerol kinase-α phosphorylation by Src on Y335 is required for activation, membrane recruitment and Hgf-induced cell motility
Diacylglycerol kinase-α phosphorylation by Src on Y335 is required for activation, membrane recruitment and Hgf-induced cell motility
复制标题
DOI：
10.1038/sj.onc.1210717
复制
发表时间：
2008-02-07
期刊：
影响因子：
8
通讯作者：
Graziani, A.
中科院分区：
文献类型：
--
作者：
Baldanzi, G.;Cutrupi, S.;Graziani, A.
二酰基甘油（DAG）激酶（Dgk）磷酸化DAG生成磷脂酸，是细胞信号传导的正调控因子或负调控因子。我们之前的研究表明，Src介导生长因子诱导的dgk - α激活，dgk - α的活性是细胞运动、增殖和血管生成所必需的。在这里，我们证明肝细胞生长因子（HGF）刺激和v-Src转化都通过一种机制，通过其富含脯氨酸的c端序列，诱导Y335上dgk - α的酪氨酸磷酸化。此外，我们发现富含脯氨酸的序列和Dgk-alpha的Y335磷酸化介导：(i)其酶活性，（ii）其分别与Src的SH3和SH2结构域相互作用的能力，（iii）其在膜上的募集。此外，我们发现Y335上dgk - α的磷酸化是HGF诱导的运动所必需的，而它在膜上通过肉豆蔻化的组成性募集足以在没有HGF的情况下触发自发运动。提供了dgk - α酪氨酸磷酸化是生长因子诱导的激活和膜募集所必需的第一个证据，这些发现强调了dgk - α作为变阻器的相关性，其激活是引发生长因子诱导的迁移信号的阈值。
Diacylglycerol (DAG) kinases (Dgk), which phosphorylate DAG to generate phosphatidic acid, act as either positive or negative key regulators of cell signaling. We previously showed that Src mediates growth factors-induced activation of Dgk-alpha, whose activity is required for cell motility, proliferation and angiogenesis. Here, we demonstrate that both hepatocytes growth factor (HGF) stimulation and v-Src transformation induce tyrosine phosphorylation of Dgk-alpha on Y335, through a mechanism requiring its proline-rich C-terminal sequence. Moreover, we show that both proline-rich sequence and phosphorylation of Y335 of Dgk-alpha mediate: (i) its enzymatic activation, (ii) its ability to interact respectively with SH3 and SH2 domains of Src, (iii) its recruitment to the membrane. In addition, we show that phosphorylation of Dgk-alpha on Y335 is required for HGF-induced motility, while its constitutive recruitment at the membrane by myristylation is sufficient to trigger spontaneous motility in absence of HGF. Providing the first evidence that tyrosine phosphorylation of Dgk-alpha is required for growth-factors-induced activation and membrane recruitment, these findings underscore its relevance as a rheostat, whose activation is a threshold to elicit growth factors-induced migratory signaling.