Molecular interaction between HAX-1 and XIAP inhibits apoptosis
Molecular interaction between HAX-1 and XIAP inhibits apoptosis
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DOI：
10.1016/j.bbrc.2010.02.084
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发表时间：
2010-03-19
影响因子：
3.1
通讯作者：
Park, Sung Goo
中科院分区：
文献类型：
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作者：
Kang, Young Ji;Jang, Mi;Park, Sung Goo
Caspase-3是Caspase的重要执行者，在细胞凋亡中起着至关重要的作用。最近发现HS1相关蛋白X1(Hax-1)是caspase-3的底物。尽管HAX-1在细胞存活和钙稳态等细胞功能中具有多种功能，但其详细的作用机制仍不清楚。在这项研究中，我们进行了蛋白质组学实验来鉴定HAX-1相互作用组。通过免疫沉淀和双向凝胶电泳法，我们鉴定了X-连锁的凋亡抑制蛋白(XIAP)是一种新的HAX-1相互作用蛋白。通过GST下拉实验，我们定义了HAX-1和XIAP的相互作用结构域，表明HAX-1与XIAP的BIR2和BIR3结构域结合，而XIAP与HAX-1的C末端结构域结合。此外，表面等离子体共振实验表明，XIAP的BIR2和BIR3结构域都以与全长XIAP相似的亲和力与HAX-1结合，表明这两个结构域都是与HAX-1紧密结合的必要条件和充分条件。结合HAX-1抑制XIAP多泛素化的观察，细胞存活率测定结果表明，HAX-1-XIAP复合体的形成通过提高XIAP对蛋白体降解的稳定性而抑制细胞凋亡。(C)2010 Elsevier Inc.保留所有权利。
Caspase-3 is an important executor caspase that plays an essential role in apoptosis. Recently, HS1-associated protein X1 (HAX-1) was found to be a substrate of caspase-3. Although HAX-1 has serve multifunctional roles in cellular functions such as cell survival and calcium homeostasis, the detailed functional mechanism of HAX-1 remains still unclear. In this study, we performed proteomic experiments to identify the HAX-1 interactome. Through immunoprecipitation and 2D gel electrophoresis, we identified X-linked inhibitor of apoptosis protein (XIAP) as a novel HAX-1-interacting protein. By performing the GST pull-down assay, we defined the interaction domains in HAX-1 and XIAP, showing that HAX-1 binds to the BIR2 and BIR3 domains of XIAP whereas XIAP binds to the C-terminal domain of HAX-1. In addition, surface plasma resonance experiments showed that both BIR2 and BIR3 domains of XIAP bind to HAX-1 with affinity similar to that of full-length XIAP, indicating that either domain is necessary and sufficient for tight binding to HAX-1. Taken together with the observation that HAX-1 suppresses the polyubiquitination of XIAP, the cell viability assay results suggest that the formation of the HAX-1-XIAP complex inhibits apoptosis by enhancing the stability of XIAP against proteosomal degradation. (C) 2010 Elsevier Inc. All rights reserved.