NF-kB regulation by p105 and p100

描述（申请人提供）：转录因子NF-？B和抑制剂I？B家族是多种细胞信号通路的关键调节因子，这些信号通路对细胞生理学，特别是免疫调节、细胞存活和增殖具有深远影响。NF-？B1（也称为p105/p50）和NF-？B2（也称为p100/p52）属于NF-？B和我？B类家庭。p105和p100是前体，它们被加工成较小的产物，p50和p52是NF-？B家族。前体作为NF-？B，包括自己加工的产品。加工必须严格监管，以产生适当比例的未加工和加工形式。许多人类疾病，如自身免疫性疾病和癌症，都与p100和p105的不受调节的加工有关。p105和p100揭示了NF-？B信令模块通过生成所有NF-？B p50和p52蛋白和抑制近一半的所有五个NF-？B蛋白。就像典型的我？B抑制剂，I？B，-然后-？，p105和p100抑制剂也经历完全降解释放NF-？B转录因子。然而，在处理事件的背景下难以观察到完整的降级事件，因此不太被重视。p105的加工是组成型的，而p100的加工是诱导型的。该建议旨在研究这两个事件之间的处理和完全降解以及耦合的生化机制。我们的假设，来自我们的初步结果和已发表的报告，是加工或缺乏它的基本调节是由几个竞争的域间和域内的相互作用，在p105和p100，这些相互作用可以改变信号。我们建议，p105-自我相互作用诱导的结构状态，有利于组成性加工，而p100只通过信号传导达到这种状态。我们进一步建议，作为完全组装的NF-？B抑制复合物，p105和p100的加工位点被掩蔽。p105和p100在这些组装的复合物必须经历完全降解细胞信号释放结合NF-？B。我们将测试我们的假设，i）确定的三维结构的p105/p100结合NF-？B用X射线晶体学，ii）确定的相互作用策略和能量的p105/p100：NF-？B络合物，和最后，iii）研究前体的加工和降解。 公共卫生相关性：我们提出的研究有可能解开长期存在的问题，即两种NF-κ B前体蛋白如何作为转录因子和NF-κ B抑制剂发挥双重功能。这两种蛋白质的失调与自身免疫疾病和癌症密切相关。目前针对多发性骨髓瘤的治疗作为异常NF-κ B活化的抑制剂发挥作用。我们的工作将在识别新的和更好的抑制剂方面发挥重要作用。

DESCRIPTION (provided by applicant): Members of the transcription factor NF-?B and inhibitor I?B families are the key regulators of diverse array of cell signaling pathways that have profound impact on cell physiology, in particular, immuno-modulation, survival and proliferation of cell. NF-?B1 (also called p105/p50) and NF-?B2 (also called p100/p52) belong to both the NF-?B and I?B families. p105 and p100 are the precursors which processed into smaller products, p50 and p52, members of the NF-?B family. Precursors function as inhibitors of NF-?B, including their own processed products. Processing must be tightly regulated to generate appropriate ratio of unprocessed and processed forms. Many human diseases, such as autoimmune diseases and cancer, are linked to unregulated processing of p100 and p105. p105 and p100 divulge highly complex regulatory events in the NF-?B signaling module by generating all of NF-?B p50 and p52 proteins and inhibiting nearly half of all five NF-?B proteins. Like the prototypical I?B inhibitors, I?B?,-? and -?, p105 and p100 inhibitors also undergo complete degradation releasing NF-?B transcription factors. However, complete degradation events are difficult to observe in the backdrop of the processing events and thus are less appreciated. Processing of p105 is constitutive whereas that of p100 is inducible. This proposal aims to study the biochemical mechanisms of processing and complete degradation and coupling between these two events. Our hypothesis, derived from our preliminary results and published reports, is that the fundamental regulation of processing or lack of it is guided by several competing inter- and intra-domain interactions in p105 and p100, and these interactions can be altered by signaling. We propose that p105-self interaction induces a structural state that is conducive to constitutive processing whereas p100 attains that state only through signaling. We further propose that as the fully assembled NF-?B inhibitory complexes, the processing sites of p105 and p100 are masked. p105 and p100 in these assembled complexes must undergo complete degradation by cell signaling to liberate bound NF-?B. We will test our hypothesis by i) determining the three-dimensional structures of p105/p100 bound to NF-?B using x- ray crystallography, ii) identifying interaction strategies and energies of the p105/p100:NF-?B complexes, and finally, iii) studying the processing and degradation of the precursors. PUBLIC HEALTH RELEVANCE: Our proposed research has the potential to unravel the long-standing question of how the two NF-kappaB precursor proteins carry out dual functions both as transcription factors and inhibitors of NF-kB. Misregulation of both these proteins are strongly linked to auto-immune diseases and cancer. Current therapy against multiple myeloma function as an inhibitor of aberrant NF-kB activation. Our work will play a major role identifying new and better inhibitors.