A small peptide promotes EphA2 kinase-dependent signaling by stabilizing EphA2 dimers.
A small peptide promotes EphA2 kinase-dependent signaling by stabilizing EphA2 dimers.
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DOI：
10.1016/j.bbagen.2016.06.004
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发表时间：
2016-09
期刊：
影响因子：
--
通讯作者：
Hristova K
中科院分区：
文献类型：
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作者：
Singh DR;Pasquale EB;Hristova K
EphA2受体酪氨酸激酶在没有ephrin配体激活的情况下促进癌细胞恶性。这种行为依赖于Ser897上EphA2的高磷酸化和酪氨酸的低磷酸化，导致细胞迁移和侵袭性增加。我们之前已经证明EphA2在没有ephrin配体结合的情况下形成二聚体，并且未配体EphA2的二聚化可以降低EphA2 Ser897的磷酸化。我们还发现了一种叫做YSA的小肽，它与EphA2结合，并与自然产生的ephrin配体竞争。在这里，我们使用定量FRET技术、Western blotting和细胞运动分析来研究YSA对EphA2二聚体稳定性和EphA2功能的影响。我们发现，YSA肽稳定EphA2二聚体，增加EphA2 Tyr磷酸化，减少Ser897磷酸化和细胞迁移。实验表明，小肽配体YSA通过稳定EphA2二聚体来降低EphA2 Ser897促肿瘤信号。这项工作是一个原理证明，EphA2在质膜中的同源相互作用可以通过药理学调节来减少受体的促肿瘤信号传导。
The EphA2 receptor tyrosine kinase is known to promote cancer cell malignancy in the absence of activation by ephrin ligands. This behavior depends on high EphA2 phosphorylation on Ser897 and low tyrosine phosphorylation, resulting in increased cell migration and invasiveness. We have previously shown that EphA2 forms dimers in the absence of ephrin ligand binding, and that dimerization of unliganded EphA2 can decrease EphA2 Ser897 phosphorylation. We have also identified a small peptide called YSA, which binds EphA2 and competes with the naturally occurring ephrin ligands. Here, we investigate the effect of YSA on EphA2 dimer stability and EphA2 function using quantitative FRET techniques, Western blotting, and cell motility assays. We find that the YSA peptide stabilizes the EphA2 dimer, increases EphA2 Tyr phosphorylation, and decreases both Ser897 phosphorylation and cell migration. The experiments demonstrate that the small peptide ligand YSA reduces EphA2 Ser897 pro-tumorigenic signaling by stabilizing the EphA2 dimer. This work is a proof-of-principle demonstration that EphA2 homointeractions in the plasma membrane can be pharmacologically modulated to decrease the pro-tumorigenic signaling of the receptor.