Vertebrate tankyrase domain structure and sterile α motif (SAM)-mediated multimerization
Vertebrate tankyrase domain structure and sterile α motif (SAM)-mediated multimerization
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DOI：
10.1042/bj20021450
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发表时间：
2003-05-15
影响因子：
4.1
通讯作者：
Price, CM
中科院分区：
文献类型：
--
作者：
De Rycker, M;Venkatesan, RN;Price, CM
端锚聚合酶I和端锚聚合酶2是两种高度相关的多聚腺苷三磷酸核糖聚合酶，与多种细胞质和核蛋白相互作用。这两种蛋白质都与端粒长度调节、胰岛素信号传导和中心体功能有关。为了更多地了解它们的作用模式，我们分离了鸡端锚聚合酶同源物，并研究了它们的相互作用伴侣和亚细胞位置。跨物种序列比较表明，端锚聚合酶结构域的结构是高度保守的，并支持划分的锚蛋白结构域为5个亚结构域，这是每个分离的高度保守的LLEAAR/K基序。Glucose-转移酶下拉实验表明，这两种蛋白质的锚蛋白结构域与鸡端粒重复因子I（TRF 1）相互作用。总细胞和核蛋白的分析显示，细胞含有大约两倍多的端锚聚合酶I的端锚聚合酶2。虽然大于或等于90%的每种蛋白质存在于细胞质中，但端锚聚合酶I和2都在细胞核中检测到。核位置连同其与TRF 1相互作用的能力，指向具有端粒功能的端锚聚合酶2。酵母双杂交和交联实验表明，这两种端锚聚合酶可以通过其不育-α基序结构域多聚化。这些结果表明端锚聚合酶可能是主支架蛋白，能够调节大蛋白复合物的组装。
Tankyrases I and 2 are two highly related poly(ADPribose) polymerases that interact with a variety of cytoplasmic and nuclear proteins. Both proteins have been implicated in telomere length regulation, insulin signalling and centrosome function. To learn more about their mode of action, we have isolated the chicken tankyrase homologues and examined their interaction partners and subcellular location. Cross-species sequence comparison indicated that tankyrase domain structure is highly conserved and supports division of the ankyrin domain into five subdomains, which are each separated by a highly conserved LLEAAR/K motif. Glutathione S-transferase pull-down experiments demonstrated that the ankyrin domains of both proteins interact with chicken telomere repeat factor I (TRF1). Analysis of total cellular and nuclear proteins revealed that cells contain approximately twice as much tankyrase I as tankyrase 2. Although greater than or equal to 90% of each protein is present in the cytoplasm, both tankyrase I and 2 were detected in the nucleus. The nuclear location together with its ability to interact with TRF1, point to tankyrase 2 having a telomeric function. Yeast two-hybrid and cross-linking experiments show that both tankyrases can multimerize through their sterile-alpha motif domains. These results indicate that tankyrases may be master scaffolding proteins, capable of regulating assembly of large protein complexes.