Insight into the molecular interaction between the cyclic nucleotide-binding homology domain and the eag domain of the hERG channel

The gating of the hERG channel is regulated by its eag domain through molecular interaction with either the cyclic nucleotide-binding homology domain (CNBHD) or the linker between transmembrane segments 4 and 5. Our NMR study on the purified CNBHD demonstrated that it contains nine β-strands and does not bind cAMP. We show that the eag domain binds to the CBND through an interface containing several disease-associated mutations. The N-terminal cap domain and R56 in the eag domain are important for the interaction with the CNBHD. Residues from the CNBHD that were affected by the interaction with the eag domain were also identified. A R56Q mutation does not cause major structural changes in the eag domain and showed reduced interaction with the CNBHD.     

食管癌组织CDC25B的表达与临床病理参数及放疗敏感性的关系研究

摘要 目的：探讨食管癌组织中细胞分裂周期蛋白25B （CDC25B）表达特点,分析其与食管癌临床病理参数和放疗敏感性的关系。方法：选择2015年1月至2018年1月我院收集的60例食管癌患者癌组织、癌旁组织的石蜡标本,采用免疫组化法检测食管癌组织和癌旁组织中CDC25B表达,分析CDC25B表达与食管癌临床病理参数的关系。所有患者均接受放疗或放化疗治疗,观察不同疗效患者CDC25B表达差异,分析CDC25B对食管癌放疗敏感性的预测价值。结果：食管癌组织中CDC25B阳性表达率高于癌旁组织（P<0.05）。CDC25B阳性表达与食管癌分化程度、TNM分期、淋巴结转移有关（P<0.05）。放疗敏感组CDC25B阳性表达率低于放疗抗拒组（P<0.05）。CDC25B预测食管癌放疗敏感性的曲线下面积（AUC）为0.718（95%CI：0.580~0.856）,灵敏度为60%,特异度为68%。结论：食管癌患者CDC25B表达上调,CDC25B阳性表达与食管癌分化程度、TNM分期、淋巴结转移恶性侵袭行为有关,CDC25B可作为食管癌放疗敏感性评估的辅助指标。