Roles of C-terminal Src kinase in the initiation and the termination of the high affinity IgE receptor-mediated signaling
Roles of C-terminal Src kinase in the initiation and the termination of the high affinity IgE receptor-mediated signaling
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DOI：
10.1074/jbc.272.41.25753
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发表时间：
1997-10-10
影响因子：
4.8
通讯作者：
Ito, K
中科院分区：
文献类型：
--
作者：
Honda, Z;Suzuki, T;Ito, K
为了分析C端Src激酶(CSK)在高亲和力IgE受体(Fc Epsilon RI)介导的信号转导中的作用，我们在大鼠嗜碱粒细胞白血病(RBL)2H3细胞中过表达了CSK，一种膜靶向的CSK(MCsk)，以及一种激酶缺陷的膜靶向的CSK(mCsk(-))。在表达CSK的细胞中，Lyn的基态比活性降低，在表达mCsk的细胞中，Lyn的比活性进一步降低。在表达mCsk(-)的细胞中，Lyn的基础比活性增加，从而表明mCsk(-)是主要的负性分子。在表达CSK的细胞中，Fc epsilon RI介导的Lyn激活的开始时间延迟，在表达mCsk的细胞中进一步延迟。在表达mCsk(-)的细胞中，Lyn激活迅速且持续时间较长。这些发现表明：(I)CSK负性调节Fc epsilon RI/Lyn的快速偶联，以及(Ii)CSK的活性可能是终止这种偶联所必需的。在表达CSK和表达mCsk的细胞中，Syk酪氨酸磷酸化、丝裂原活化蛋白(MAP)激活、细胞内钙浓度([Ca~(2+)](I))升高和组胺释放等一系列事件的开始都逐渐延迟。Syk磷酸化和MAPK激活的持续时间也与Lyn激活的持续时间密切相关，但[Ca~(2+)](I)升高和组胺释放遵循不同的时间模式：在表达CSK的细胞和表达mCsk的细胞中，延迟反应导致持续的[Ca~(2+)](I)振荡和组胺释放，而在亲本细胞和表达mCsk(-)的细胞中的快速反应迅速消退。这些发现进一步证明，Fc epsilon RI介导的信号的启动受Src家族蛋白酪氨酸激酶的上游调控，其终止受Lyn依赖(Syk和MAP激酶)和非依赖性([Ca2+](I)升高和组胺释放)机制的调节。
As an attempt to analyze the roles of C-terminal Src kinase (Csk) in the high affinity IgE receptor (Fc epsilon RI)-mediated signaling, we overexpressed Csk, a membrane-targeted form of Csk (mCsk), and a kinase-defective, membrane-targeted form of Csk (mCsk(-)) in rat basophil leukemia (RBL) 2H3 cells. Specific activity of Lyn at the basal state was decreased in Csk-expressing cells, and further decreased in mCsk-expressing cells. In mCsk(-)-expressing cells, basal specific activity of Lyn was increased, thereby indicating that mCsk(-) functioned as a dominant negative molecule. The onset of Fc epsilon RI-mediated Lyn activation was delayed in Csk-expressing cells, and further delayed in mCsk-expressing cells. In mCsk(-)-expressing cells, Lyn activation was rapid and quite long lasting. These findings indicate (i) Csk negatively regulates rapid Fc epsilon RI/Lyn coupling, and (ii) Csk activity is potentially required for its termination. The onsets of the series of events including tyrosyl phosphorylation of Syk, mitogen-activated protein (MAP) kinase activation, elevation of intracellular calcium concentration ([Ca2+](i)), and histamine release were all stepwisely delayed in Csk-expressing cells and in mCsk-expressing cells. The durations of Syk phosphorylation and MAP kinase activation also closely correlated with those of Lyn activation, but [Ca2+](i) elevation and histamine release followed different temporal patterns: the delayed responses in Csk-expressing cells and in mCsk-expressing cells led to sustained [Ca2+](i) oscillation and histamine release, while the prompt responses in parent cells and mCsk(-)-expressing cells rapidly subsided. These findings provide further evidence that the initiations of the Fc epsilon RI-mediated signals are upstreamly regulated by Src family protein tyrosine kinases and revealed that their terminations are regulated by Lyn-dependent (Syk and MAP kinase) and -independent ([Ca2+](i) elevation and histamine release) mechanisms.