Structural Basis for Ubiquitin Recognition by a Novel Domain from Human Phospholipase A2-activating Protein
Structural Basis for Ubiquitin Recognition by a Novel Domain from Human Phospholipase A2-activating Protein
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DOI：
10.1074/jbc.m109.009126
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发表时间：
2009-07-10
影响因子：
4.8
通讯作者：
Hu, Hong-Yu
中科院分区：
文献类型：
--
作者：
Fu, Qing-Shan;Zhou, Chen-Jie;Hu, Hong-Yu
泛素(Ub)是从酵母到人类的所有真核生物中都保守的一种重要修饰物。磷脂酶A(2)激活蛋白(PlaA)是酵母DOA1/UFD3的哺乳动物同源物，被认为能够与Ub结合，在内质网相关的降解、囊泡形成和DNA损伤反应中发挥重要作用。我们已经从人的PlaA家族泛素结合区(残基386-465，即PfUC)中鉴定出一个能与Ub结合的核心结构域，并通过核磁共振方法阐明了其溶液结构和Ub结合方式。PFUC结构域通过顺式/反式异构化在溶液中具有相同的两种构象群，而两种异构体表现出几乎相同的Ub结合能力。该结构域具有由4个β链和2个α螺旋组成的新型折叠结构，PfUC上的Ub结合位点位于α2螺旋表面，在一定程度上类似于UBA、CUE和UIM结构域。本研究为Ub从Plaa家族蛋白中识别新的Pfu结构域提供了结构基础和生化信息，该蛋白可能在内质网相关的降解过程中连接泛素化和降解。
Ubiquitin (Ub) is an essential modifier conserved in all eukaryotes from yeast to human. Phospholipase A(2)-activating protein (PLAA), a mammalian homolog of yeast DOA1/UFD3, has been proposed to be able to bind with Ub, which plays important roles in endoplasmic reticulum-associated degradation, vesicle formation, and DNA damage response. We have identified a core domain from the PLAA family ubiquitin-binding region of human PLAA (residues 386-465, namely PFUC) that can bind Ub and elucidated its solution structure and Ub-binding mode by NMR approaches. The PFUC domain possesses equal population of two conformers in solution by cis/trans-isomerization, whereas the two isomers exhibit almost equivalent Ub binding abilities. This domain structure takes a novel fold consisting of four beta-strands and two alpha-helices, and the Ub-binding site on PFUC locates in the surface of alpha 2-helix, which is to some extent analogous to those of UBA, CUE, and UIM domains. This study provides structural basis and biochemical information for Ub recognition of the novel PFU domain from a PLAA family protein that may connect ubiquitination and degradation in endoplasmic reticulum-associated degradation.