MERIT40-dependent recruitment of tankyrase to damaged DNA and its implication for cell sensitivity to DNA-damaging anticancer drugs.
MERIT40-dependent recruitment of tankyrase to damaged DNA and its implication for cell sensitivity to DNA-damaging anticancer drugs.
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DOI：
10.18632/oncotarget.26312
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发表时间：
2018-11-09
期刊：
影响因子：
--
通讯作者：
Seimiya, Hiroyuki
中科院分区：
文献类型：
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作者：
Okamoto, Keiji;Ohishi, Tomokazu;Seimiya, Hiroyuki
端锚聚合酶（Tankyrase）是聚腺苷二磷酸核糖聚合酶（poly（ADP-ribose）polymerase，PARP）家族的一员，通过与多种靶蛋白相互作用，调节细胞内的多种反应，如端粒维持、Wnt/β-catenin信号传导和细胞周期进程。端锚聚合酶含有一长段24个锚蛋白重复序列，进一步分为五个亚结构域，称为ANK重复序列簇（ARC）。每个ARC作为一个独立的配体结合单位，这意味着端锚聚合酶作为一个平台，多个蛋白质-蛋白质相互作用。此外，端锚聚合酶分布到各种细胞内位点，表明潜在的不同但尚未确定的生理功能。为了探索端锚聚合酶的新功能，我们进行了液相色谱-质谱分析，并确定BRE-BRCC 36-MERIT 40复合物，同源重组的调节剂，作为端锚聚合酶结合蛋白。在复合物组分中，MERIT 40通过端锚聚合酶结合共有基序与端锚聚合酶直接相关，如先前报道的。在X射线照射的非小细胞肺癌细胞中，端锚聚合酶以MERIT 40依赖性方式定位于DNA双链断裂位点。MERIT 40敲低增加了细胞对X射线的敏感性，而野生型，但不是端锚聚合酶未结合的突变体，MERIT 40拯救了敲低细胞的表型。端锚聚合酶抑制剂，如G 007-LK和XAV 939，增加了细胞对X射线照射和诱导DNA双链断裂的抗癌药物的敏感性。这些观察结果表明，端锚聚合酶在DNA损伤修复反应中起作用，并暗示端锚聚合酶抑制剂在与DNA损伤抗癌药物联合治疗中的潜在治疗效用。
Tankyrase, a member of the poly(ADP-ribose) polymerase (PARP) family, regulates various intracellular responses, such as telomere maintenance, Wnt/beta-catenin signaling and cell cycle progression through its interactions with multiple target proteins. Tankyrase contains a long stretch of 24 ankyrin repeats that are further divided into five subdomains, called ANK repeat clusters (ARCs). Each ARC works as an independent ligand-binding unit, which implicates tankyrase as a platform for multiple protein-protein interactions. Furthermore, tankyrase distributes to various intracellular loci, suggesting potential distinct but yet unidentified physiological functions. To explore the novel functions of tankyrase, we performed liquid chromatography-mass spectrometry analysis and identified the BRE-BRCC36-MERIT40 complex, a regulator of homologous recombination, as tankyrase-binding proteins. Among the complex components, MERIT40 was directly associated with tankyrase via a tankyrase-binding consensus motif, as previously reported. In X-ray-irradiated non-small cell lung cancer cells, tankyrase localized to DNA double-stranded break sites in a MERIT40-dependent manner. MERIT40 knockdown increased the cell sensitivity to X-ray, whereas the wild-type, but not the tankyrase-unbound mutant, MERIT40 rescued the phenotype of the knockdown cells. Tankyrase inhibitors, such as G007-LK and XAV939, increased the cellular sensitivity to X-ray irradiation and anticancer drugs that induce DNA double-stranded breaks. These observations suggest that tankyrase plays a role in the DNA damage repair response and implicates a potential therapeutic utility of tankyrase inhibitors in combination treatments with DNA-damaging anticancer drugs.