The SH3 domain of Fyn kinase interacts with and induces liquid-liquid phase separation of the low-complexity domain of hnRNPA2
The SH3 domain of Fyn kinase interacts with and induces liquid-liquid phase separation of the low-complexity domain of hnRNPA2
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DOI：
10.1074/jbc.ra118.005120
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发表时间：
2018-12-21
影响因子：
4.8
通讯作者：
Fawzi, Nicolas L.
中科院分区：
文献类型：
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作者：
Amaya, Joshua;Ryan, Veronica H.;Fawzi, Nicolas L.
将蛋白质和核酸液-液相分离成无膜细胞器（MLO），在空间上组织细胞成分和反应。 RNA 结合蛋白异质核核糖核蛋白 A2 (hnRNPA2) 在神经元和少突胶质细胞中称为运输颗粒的 MLO 中携带 mRNA 靶标。在局部翻译位点，hnRNPA2 被酪氨酸蛋白激酶 Fyn 磷酸化，释放 mRNA 进行翻译。 Fyn 通过其 SH3 结构域 (Fyn-SH3) 识别目标。然而，hnRNPA2 缺乏规范的 SH3 结合序列，这就提出了 Fyn-SH3 如何在相分离运输颗粒中结合 hnRNPA2 的问题。在这里，我们表征了 hnRNPA2 低复杂性结构域 (LC) 与 Fyn-SH3 相互作用的结构细节以及 Fyn-SH3 对 hnRNPA2 相分离的影响。我们结合体外显微镜和溶液核磁共振波谱来评估 hnRNPA2 和 Fyn-SH3 组装成体外相分离颗粒的情况，并探讨它们相互作用的结构细节。我们观察到 Fyn-SH3 诱导 hnRNPA2 LC 相分离，并且 Fyn-SH3 掺入体外 hnRNPA2 LC 颗粒中。此外，我们在 Fyn-SH3 表面鉴定了 hnRNPA2 LC 相互作用位点。我们的数据提供了 hnRNPA2 LC 如何与 Fyn 相互作用的结构视图。据我们所知，我们的研究提供了第一个单球状结构域诱导无序 MLO 支架蛋白相分离的例子。
Liquid-liquid phase separation of proteins and nucleic acids into membraneless organelles (MLOs) spatially organizes cellular components and reactions. The RNA-binding protein heterogeneous nuclear ribonucleoprotein A2 (hnRNPA2) carries mRNA targets in MLOs called transport granules in neurons and oligodendrocytes. At sites of local translation, hnRNPA2 is phosphorylated by the tyrosine protein kinase Fyn, releasing the mRNA for translation. Fyn recognizes targets through its SH3 domain (Fyn-SH3). However, hnRNPA2 lacks canonical SH3-binding sequences, raising the question of how Fyn-SH3 binds hnRNPA2 in phase-separated transport granules. Here, we characterize the structural details of the interaction of the hnRNPA2 low-complexity domain (LC) with Fyn-SH3 and the effect of Fyn-SH3 on hnRNPA2 phase separation. We combined in vitro microscopy and solution NMR spectroscopy to evaluate assembly of hnRNPA2 and Fyn-SH3 into in vitro phase-separated granules and probe the structural details of their interaction. We observed that Fyn-SH3 induces hnRNPA2 LC phase separation and that Fyn-SH3 is incorporated into in vitro hnRNPA2 LC granules. Moreover, we identified hnRNPA2 LC interaction sites on the surface of Fyn-SH3. Our data offer a structural view of how hnRNPA2 LC may interact with Fyn. To our knowledge, our study provides the first example of a single globular domain inducing phase separation of a disordered MLO scaffold protein.