Structural and functional studies of the IkappaB kinase (IKK) complex

描述（由申请人提供）：核因子中的转录因子？B (NF - ?B)家族是进化上保守的免疫和炎症反应的主要调节者。它们在许多受体的连接下被激活，包括t细胞受体、b细胞受体、肿瘤坏死因子（TNF）受体超家族成员和toll样受体/白细胞介素-1受体（TLR/IL-1R）超家族成员。我吗?B激酶（IKK）由IKKa和IKK¿组成，是NF-？B活化并介导两个NF-？B激活途径。典型的NF-？B途径由微生物和病毒感染以及促炎细胞因子触发，依赖于IKK的磷酸化和激活。替代途径由TNF细胞因子家族的某些成员触发，并选择性地激活IKKa。活化的IKK磷酸化I？b，导致它们的多泛素化，随后被蛋白酶体降解。释放的NF-？B二聚体转移到细胞核介导转录。因为它在NF-？B活化，IKK，特别是IKK¿，已成为许多人类疾病的潜在治疗靶点。调节蛋白NEMO(也称为IKK？或FIP-3)与IKKa和/或IKK¿相互作用形成IKKa、IKK¿或IKKa/¿整体复合物。完整的IKK¿holo复合物的分子质量约为700-900kD，含有IKK2和NEMO的多个拷贝。IKKa和IKK¿都包含以下保守的可识别结构域：激酶结构域（KD），亮氨酸拉链结构域（LZ），螺旋环螺旋结构域（HLH）和c端nemo结合结构域（NBD）。NEMO包含一个n端激酶结合域（KBD），一个最小寡聚化域（MOD），也是泛素结合域（UBD）和一个c端锌指结构域（ZF）。IKK和NF-？B信号引起了极大的关注，发表了3万多篇有关该主题的论文。尽管IKK具有重要的生物学意义，但没有一个成功的结构测定报告，这表明项目的难度。为了阐明IKK功能的分子基础并协助发现IKK抑制剂，我们提出了一系列关于IKK的结构和功能研究，特别是IKK¿及其调控蛋白NEMO。

DESCRIPTION (provided by applicant): Transcription factors in the nuclear factor ?B (NF-?B) family are evolutionarily conserved master regulators of immune and inflammatory responses. They are activated in response to ligation of many receptors including T-cell receptors, B-cell receptors, members of the tumor necrosis factor (TNF) receptor superfamily and the Toll-like receptor/interleukin-1 receptor (TLR/IL-1R) superfamily. The I?B kinase (IKK), comprising IKKa and IKK¿, is at the heart of NF-?B activation and mediates two NF-?B activation pathways. The canonical NF-?B pathway is triggered by microbial and viral infections and pro-inflammatory cytokines and is dependent on IKK¿ phosphorylation and activation. The alternative pathway is triggered by certain members of the TNF cytokine family and selectively activates IKKa. Activated IKK phosphorylates I?Bs, leading to their polyubiquitination and subsequent degradation by the proteasome. The freed NF-?B dimers translocate to the nucleus to mediate transcription. Because of its importance in NF-?B activation, IKK, especially IKK¿, has become a potential therapeutic target for many human diseases. The regulatory protein NEMO (also known as IKK? or FIP-3) interacts with IKKa and/or IKK¿ to form the IKKa, IKK¿ or IKKa/¿ holo-complex. The intact IKK¿ holo-complex is approximately 700-900kD in molecular mass containing multiple copies of IKK2 and NEMO. IKKa and IKK¿ both contain the following conserved recognizable domains: a kinase domain (KD), a leucine zipper domain (LZ), a helix loop helix domain (HLH) and a C-terminal NEMO-binding domain (NBD). NEMO contains an N-terminal kinase-binding domain (KBD), a minimal oligomerization domain (MOD) that is also the ubiquitin binding domain (UBD) and a C-terminal zinc finger domain (ZF). IKK and NF-?B signaling has attracted tremendous attention with more than 30,000 papers published on the subject. Despite the biological importance, not a single successful structure determination has been reported on IKK, an indication on the difficulty of the project. To elucidate the molecular basis of IKK function and to assist the discovery of IKK inhibitors, we propose a series of structural and functional studies on IKK, in particular, IKK¿ and its regulatory protein NEMO.