State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin, 300071, China.
State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin, 300071, China.
Biochem Biophys Res Commun. 2021 May 14;553:92-98. doi: 10.1016/j.bbrc.2021.03.065. Epub 2021 Mar 22.
NF2/Merlin is an upstream regulator of hippo pathway, and it has two states: an auto-inhibited "closed" state and an active "open" form. Previous studies showed that Drosophila Merlin adopts a more closed conformation. However, the molecular mechanism of conformational regulation remains poorly understood. Here, we first confirmed the strong interaction between FERM and the C-terminal domain (CTD) of Merlin, and then determined the crystal structure of the FERM/CTD complex, which reveals the structural basis of Merlin adopting a more closed conformation compared to its human cognate NF2. Interestingly, we found that the conserved lipid-binding site of Merlin might be masked by a linker. Confocal analyses confirmed that all putative lipid-binding site are very important for the membranal location of Merlin. More, we found that the phosphomimic Thr616Asp mutation weakens the interaction between FERM and CTD of Merlin. Collectively, the crystal structure of the FERM/CTD complex not only provides a mechanistic explanation of functionally dormant conformation of Merlin may also serve as a foundation for revealing the mechanism of conformational regulation of Merlin.
NF2/Merlin 是 hippo 通路的上游调节剂，它有两种状态：自动抑制的“关闭”状态和活跃的“打开”形式。先前的研究表明，果蝇 Merlin 采用了更封闭的构象。然而，构象调节的分子机制仍知之甚少。在这里，我们首先证实了 FERM 和 Merlin 的 C 端结构域（CTD）之间的强相互作用，然后确定了 FERM/CTD 复合物的晶体结构，该结构揭示了 Merlin 与人类同源物 NF2 相比采用更封闭构象的结构基础。有趣的是，我们发现 Merlin 的保守脂质结合位点可能被一个接头掩盖。共聚焦分析证实，所有假定的脂质结合位点对于 Merlin 的膜定位都非常重要。此外，我们发现磷酸模拟 Thr616Asp 突变削弱了 FERM 和 Merlin CTD 之间的相互作用。总之，FERM/CTD 复合物的晶体结构不仅为 Merlin 功能休眠构象提供了一个机制解释，也为揭示 Merlin 构象调节的机制奠定了基础。
