Rab35/ACAP2 and Rab35/RUSC2 Complex Structures Reveal Molecular Basis for Effector Recognition by Rab35 GTPase
Rab35/ACAP2 and Rab35/RUSC2 Complex Structures Reveal Molecular Basis for Effector Recognition by Rab35 GTPase
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Rab35/ACAP2 和 Rab35/RUSC2 复杂结构揭示了 Rab35 GTPase 识别效应子的分子基础
DOI：
10.1016/j.str.2019.02.008
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发表时间：
2019-05-07
期刊：
影响因子：
5.7
通讯作者：
Zhang, Rongguang
中科院分区：
文献类型：
--
作者：
Lin, Lin;Shi, Yingdong;Zhang, Rongguang
Rab35是膜运输的主要调节因子，调节多种细胞过程并与多种人类疾病有关。虽然已经确定了许多效应物，但rab35效应物相互作用的分子基础仍不清楚。在这里，我们提供了Rab35配合物的高分辨率晶体结构，其两个特定的效应器ACAP2和RUSC2分别。在Rab35/ACAP2复合体结构中，Rab35结合末端锚蛋白重复序列和ACAP2的c端延伸α螺旋，揭示了Rab35和锚蛋白重复序列的先前未被表征的结合模式。在Rab35/RUSC2复合体结构中，RUSC2的Arg1015作为“伪精氨酸手指”，稳定gtp结合的Rab35，从而促进Rab35/RUSC2复合体的组装。结构分析使我们能够设计特异性的Rab35突变体，能够消除Rab35/ACAP2和Rab35/RUSC2相互作用，但不干扰其他效应体结合。原子结构也为rab35效应界面上发现的疾病相关突变提供了可能的解释。
Rab35, a master regulator of membrane trafficking, regulates diverse cellular processes and is associated with various human diseases. Although a number of effectors have been identified, the molecular basis of Rab35-effector interactions remains unclear. Here, we provide the high-resolution crystal structures of Rab35 in complex with its two specific effectors ACAP2 and RUSC2, respectively. In the Rab35/ACAP2 complex structure, Rab35 binds to the terminal ankyrin repeat and a C-terminal extended alpha helix of ACAP2, revealing a previously uncharacterized binding mode both for Rabs and ankyrin repeats. In the Rab35/RUSC2 complex structure, Arg1015 of RUSC2 functions as a "pseudo-arginine finger'' that stabilizes the GTP-bound Rab35, thus facilitating the assembly of Rab35/RUSC2 complex. The structural analysis allows us to design specific Rab35 mutants capable of eliminating Rab35/ACAP2 and Rab35/RUSC2 interactions, but not interfering with other effector bindings. The atomic structures also offer possible explanations to disease-associated mutants identified at the Rab35-effector interfaces.