Wang Keping, Qiu Tiefeng, Li Xianwen
a Department of Thoracic Surgery , Nanjing Chest Hospital , Nanjing , China.
b Departments of Respiratory , Affiliated Wujin Hospital of Jiangsu University , Changzhou , China.
Cancer Invest. 2016 May 27;34(5):231-6. doi: 10.1080/07357907.2016.1183024. Epub 2016 May 21.
The human securin is an oncogenic transcription factor that has been found to promote migration and invasion of lung cancer and many other tumors. The protein contains a PxxP motif that can be recognized and bound by diverse cellular partners via Src homology (SH3) domain to regulate biological and pathological events. The motif is covered by a decapeptide segment (161)LGPPSPVKMP(170) (SecPeptide) as the potential binding site of SH3 domains. Here, we attempted to systemically identify the SH3 binding partners of human securin in lung cancer and to characterize the intermolecular interaction between SecPeptide and the identified SH3 domains. A bioinformatics protocol that integrated literature curation, complex structural modeling, and binding affinity analysis was described to perform systematic search against an array of SH3-containing proteins involved in lung cancer signaling pathway and, consequently, three putative domains, namely GRB2, CRK, and RasGAP, were identified that have high potential to recognize and bind SecPeptide. The molecular mechanism and biological implication underlying the intermolecular interaction between these domains and SecPetide were investigated at structural and energetic level. Surface plasmon resonance assay revealed a high or moderate affinity of SecPeptide and its two mutants binding to CRK-SH3 domain with dissociation constants Kd = 79.8, 24.2, and 64.6 µM, respectively.
人securin是一种致癌转录因子，已被发现可促进肺癌和许多其他肿瘤的迁移和侵袭。该蛋白包含一个PxxP基序，不同的细胞伴侣可通过Src同源（SH3）结构域识别并结合该基序，以调节生物学和病理学事件。该基序被一个十肽片段（161）LGPPSPVKMP（170）（Sec肽）覆盖，作为SH3结构域的潜在结合位点。在此，我们试图系统地鉴定人securin在肺癌中的SH3结合伴侣，并表征Sec肽与鉴定出的SH3结构域之间的分子间相互作用。我们描述了一种生物信息学方法，该方法整合了文献整理、复杂结构建模和结合亲和力分析，以对一系列参与肺癌信号通路的含SH3蛋白进行系统搜索，结果鉴定出三个推定结构域，即GRB2、CRK和RasGAP，它们具有识别和结合Sec肽的高潜力。在结构和能量水平上研究了这些结构域与Sec肽之间分子间相互作用的分子机制和生物学意义。表面等离子体共振分析显示，Sec肽及其两个突变体与CRK-SH3结构域具有高亲和力或中等亲和力，解离常数Kd分别为79.8、24.2和64.6 μM。
