Identification of phosphotyrosine binding domain-containing proteins as novel downstream targets of the EphA8 signaling function
Identification of phosphotyrosine binding domain-containing proteins as novel downstream targets of the EphA8 signaling function
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DOI：
10.1128/mcb.00794-07
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发表时间：
2007-12-01
影响因子：
5.3
通讯作者：
Park, Soochul
中科院分区：
文献类型：
--
作者：
Shin, Jongdae;Gu, Changkyu;Park, Soochul
由于具有调节复杂信号网络的能力，Eph受体和ephrin参与了多种细胞过程，包括形态和运动。在这里，我们发现含有磷酸酪氨酸结合（PTB）结构域的蛋白AIDA-1b和Odin在响应配体刺激时与EphA8受体紧密相关。AIDA-1b和Odin都属于锚蛋白重复和无菌α基序结构域（Anks）蛋白家族。Anks家族蛋白的PTB结构域对其与EphA8近膜结构域的结合至关重要，而EphA8酪氨酸激酶活性并不需要这种蛋白-蛋白相互作用。此外，我们发现Odin在哺乳动物细胞中是EphA8生理上更相关的伴侣。有趣的是，在HEK293细胞中，单独过表达Odin PTB结构域会减弱epha8介导的细胞迁移抑制，这表明它是内源性Odin蛋白的显性阴性突变体。更重要的是，小干扰rna介导的Odin沉默显著降低了ephrina5诱导的EphA8信号效应，从而抑制了HEK293细胞的细胞迁移，并使Neuro2a细胞的生长神经突退缩。综上所述，我们的发现支持了Anks的可能功能；家族蛋白作为EphA8信号通路的支架蛋白。
Eph receptors and ephrins have been implicated in a variety of cellular processes, including morphology and motility, because of their ability to modulate intricate signaling networks. Here we show that the phosphotyrosine binding (PTB) domain-containing proteins AIDA-1b and Odin are tightly associated with the EphA8 receptor in response to ligand stimulation. Both AIDA-1b and Odin belong to the ankyrin repeat and sterile alpha motif domain-containing (Anks) protein family. The PTB domain of Anks family proteins is crucial for their association with the juxtamembrane domain of EphA8, whereas EphA8 tyrosine kinase activity is not required for this protein-protein interaction. In addition, we found that Odin is a more physiologically relevant partner of EphA8 in mammalian cells. Interestingly, overexpression of the Odin PTB domain alone attenuated EphA8-mediated inhibition of cell migration in HEK293 cells, suggesting that it acts as a dominant-negative mutant of the endogenous Odin protein. More importantly, small interfering RNA-mediated Odin silencing significantly diminished ephrinA5-induced EphA8 signaling effects, which inhibit cell migration in HEK293 cells and retract growing neurites of Neuro2a cells. Taken together, our findings support a possible function for Anks; family proteins as scaffolding proteins of the EphA8 signaling pathway.