Mechanism of the interaction between the intrinsically disordered C-terminus of the pro-apoptotic ARTS protein and the Bir3 domain of XIAP.
Mechanism of the interaction between the intrinsically disordered C-terminus of the pro-apoptotic ARTS protein and the Bir3 domain of XIAP.
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DOI：
10.1371/journal.pone.0024655
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Friedler A
中科院分区：
文献类型：
--
作者：
Reingewertz TH;Shalev DE;Sukenik S;Blatt O;Rotem-Bamberger S;Lebendiker M;Larisch S;Friedler A
ARTS(Sept4_I2)是一种线粒体促凋亡蛋白，具有肿瘤抑制作用。它在白血病和淋巴瘤患者中的表达显著减少。ARTS通过与其BI3结构域相互作用而结合并抑制XIAP(X连锁的凋亡抑制蛋白)。ARTS通过蛋白酶体途径促进XIAP的降解。通过这样做，ARTS消除了XIAP对caspase的抑制，并使细胞凋亡得以进行。ARTS在其C-末端结构域(CTD，残基248-274)含有27个独特的残基，对XIAP结合是重要的。在这里，我们描述了这种相互作用的分子细节。生物物理和计算方法表明，在生理条件下，ARTS的CTD本质上是无序的。核磁共振和荧光光谱证实了ARTS CTD与BI3的直接结合。ARTS CTD中的Bir3相互作用区被定位到ARTS残基266-274，这是蛋白质中的9个C末端残基。ARTS 266-274的丙氨酸扫描显示了几个残基对Bir3结合的重要性，其中His268和Cys273贡献最大。添加还原剂阻止了与Bir3的结合。ART 266-274的二聚体，通过将半胱氨酸残基氧化成具有类似亲和力的二硫键而形成，可能是与BI3相互作用所必需的。对ARTS-BI3相互作用的详细分析为将其作为抗癌药物设计的靶点提供了基础：它将使开发出模拟ARTS CTD的化合物，消除IAP对caspase的抑制，从而诱导细胞凋亡。
ARTS (Sept4_i2) is a mitochondrial pro-apoptotic protein that functions as a tumor suppressor. Its expression is significantly reduced in leukemia and lymphoma patients. ARTS binds and inhibits XIAP (X-linked Inhibitor of Apoptosis protein) by interacting with its Bir3 domain. ARTS promotes degradation of XIAP through the proteasome pathway. By doing so, ARTS removes XIAP inhibition of caspases and enables apoptosis to proceed. ARTS contains 27 unique residues in its C-terminal domain (CTD, residues 248–274) which are important for XIAP binding. Here we characterized the molecular details of this interaction. Biophysical and computational methods were used to show that the ARTS CTD is intrinsically disordered under physiological conditions. Direct binding of ARTS CTD to Bir3 was demonstrated using NMR and fluorescence spectroscopy. The Bir3 interacting region in ARTS CTD was mapped to ARTS residues 266–274, which are the nine C-terminal residues in the protein. Alanine scan of ARTS 266–274 showed the importance of several residues for Bir3 binding, with His268 and Cys273 contributing the most. Adding a reducing agent prevented binding to Bir3. A dimer of ARTS 266–274 formed by oxidation of the Cys residues into a disulfide bond bound with similar affinity and was probably required for the interaction with Bir3. The detailed analysis of the ARTS – Bir3 interaction provides the basis for setting it as a target for anti cancer drug design: It will enable the development of compounds that mimic ARTS CTD, remove IAPs inhibition of caspases, and thereby induce apoptosis.