Structural Fine-Tuning of MIT-Interacting Motif 2 (MIM2) and Allosteric Regulation of ESCRT-III by Vps4 in Yeast
Structural Fine-Tuning of MIT-Interacting Motif 2 (MIM2) and Allosteric Regulation of ESCRT-III by Vps4 in Yeast
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DOI：
10.1016/j.jmb.2016.04.007
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发表时间：
2016-06-05
影响因子：
5.6
通讯作者：
Mizuguchi, Mineyuki
中科院分区：
文献类型：
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作者：
Kojima, Rieko;Obita, Takayuki;Mizuguchi, Mineyuki
运输所需的内体分选复合体（ESCRT）促进膜重塑，如多泡体生物发生，包膜病毒出芽和细胞分裂。在酵母中，Vps4通过分解ESCRT蛋白在腔内囊泡形成中起着至关重要的作用。ESCRT-III蛋白通过Vps4的微管相互作用和运输（MIT）结构域和ESCRT-III蛋白的c端MIT相互作用基序（MIM）之间的相互作用将Vps4招募到内体膜上。在这里，我们确定了Vps4 MIT与ESCRT-III成员Vps20在配合物中的晶体结构，并发现Vps20采用独特的MIM2构象。基于与其他已知的MIM2的结构比较，我们改进了MIM2的一致序列。我们已经证明，另一种ESCRT-III蛋白Ist1通过其c端MIMI与Vps4 MIT结合，具有比Vps2更高的亲和力，但通过表面等离子体共振缺乏MIM2。令人惊讶的是，Ist1 MIMI与Vfa1 （Vps4的调节因子）的MIM2竞争，以结合Vps4 MIT，即使这些MIMs结合在MIT上的非重叠位点。这些发现为了解Vps4对ESCRT- iii的mim的变构识别以及在膜重塑的最后一步对ESCRT机制的调控提供了见解。(C) 2016 Elsevier Ltd.版权所有。
The endosomal sorting complex required for transport (ESCRT) facilitates roles in membrane remodeling, such as multivesicular body biogenesis, enveloped virus budding and cell division. In yeast, Vps4 plays a crucial role in intraluminal vesicle formation by disassembling ESCRT proteins. Vps4 is recruited by ESCRT-III proteins to the endosomal membrane through the interaction between the microtubule interacting and trafficking (MIT) domain of Vps4 and the C-terminal MIT-interacting motif (MIM) of ESCRT-III proteins. Here, we have determined the crystal structure of Vps4 MIT in a complex with Vps20, a member of ESCRT-III, and revealed that Vps20 adopts a unique MIM2 conformation. Based on structural comparisons with other known MIM2s, we have refined the consensus sequence of MIM2. We have shown that another ESCRT-III protein, Ist1, binds to Vps4 MIT via its C-terminal MIMI with higher affinity than Vps2, but lacks MIM2 by surface plasmon resonance. Surprisingly, the Ist1 MIMI competed with the MIM2 of Vfa1, a regulator of Vps4, for binding to Vps4 MIT, even though these MIMs bind in non-overlapping sites on the MIT. These findings provide insight into the allosteric recognition of MIMs of ESCRT-III by Vps4 and also the regulation of ESCRT machinery at the last step of membrane remodeling. (C) 2016 Elsevier Ltd. All rights reserved.