Siddiqui Mohd Quadir, Rajpurohit Yogendra S, Thapa Pankaj S, Maurya Ganesh Kumar, Banerjee Kuheli, Khan Mudassar Ali, Panda Pragnya, Hasan Syed K, Gadewal Nikhil, Misra Hari S, Varma Ashok K
Advanced Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai, Maharashtra 410 210, India; Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400 094, India.
Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
Int J Biol Macromol. 2017 Nov;104(Pt A):1338-1344. doi: 10.1016/j.ijbiomac.2017.05.166. Epub 2017 Jul 4.
Fanconi anemia (FA), a cancer predisposition syndrome exhibits hallmark feature of radial chromosome formation, and hypersensitivity to DNA crosslinking agents. A set of FA pathway proteins mainly FANCI, FANCD2 and BRCA2 are expressed to repair the covalent crosslink between the dsDNA. However, FA, BRCA pathways play an important role in DNA ICL repair as well as in homologous recombination repair, but the presumptive role of FA-BRCA proteins has not clearly explored particularly in context to function associated protein-protein interactions (PPIs). Here, in-vivo, in-vitro and in-silico studies have been performed for functionally relevant domains of FANCI, FANCD2 and BRCA2. To our conclusion, FANCI ARM repeat interacts with FANCD2 CUE domain and BRCA2 C-terminal region. Interestingly, FANCD2 CUE domain also interacts strongly with BRCA2 C-terminal region. Interactions between BRCA2 CTR and functionally relevant mutations Ser222Ala (cell cycle checkpoint mutant) and Leu231Arg (DNA ICL repair mutant) present in FANCD2 CUE domain have been analysed. To our finding, these mutations abrogate the binding between FANCD2 CUE domain and BRCA2 CTR. Furthermore, (1) different domain of FANCI, FANCD2 and BRCA2 are playing important role in PPIs, (2) mutations cause the impairment in the PPIs which in turn may disrupt the DNA ICL repair mechanism.
范可尼贫血（FA）是一种癌症易感综合征，具有染色体径向形成的标志性特征，并且对DNA交联剂高度敏感。一组FA通路蛋白，主要是FANCI、FANCD2和BRCA2，表达出来以修复双链DNA之间的共价交联。然而，FA、BRCA通路在DNA链间交联修复以及同源重组修复中都发挥着重要作用，但FA - BRCA蛋白的假定作用尚未得到明确探索，特别是在与功能相关的蛋白质 - 蛋白质相互作用（PPI）方面。在此，针对FANCI、FANCD2和BRCA2的功能相关结构域进行了体内、体外和计算机模拟研究。我们的结论是，FANCI的ARM重复序列与FANCD2的CUE结构域和BRCA2的C末端区域相互作用。有趣的是，FANCD2的CUE结构域也与BRCA2的C末端区域强烈相互作用。分析了BRCA2 C末端区域与FANCD2 CUE结构域中存在的功能相关突变Ser222Ala（细胞周期检查点突变体）和Leu231Arg（DNA链间交联修复突变体）之间的相互作用。我们的发现是，这些突变消除了FANCD2 CUE结构域与BRCA2 C末端区域之间的结合。此外，（1）FANCI、FANCD2和BRCA2的不同结构域在蛋白质 - 蛋白质相互作用中发挥着重要作用，（2）突变导致蛋白质 - 蛋白质相互作用受损，进而可能破坏DNA链间交联修复机制。
