Structural characterization of interactions between transactivation domain 1 of the p65 subunit of NF-κB and transcription regulatory factors.
Structural characterization of interactions between transactivation domain 1 of the p65 subunit of NF-κB and transcription regulatory factors.
复制标题
DOI：
10.1093/nar/gkx146
复制
发表时间：
2017-05-19
影响因子：
14.9
通讯作者：
Omichinski JG
中科院分区：
文献类型：
--
作者：
Lecoq L;Raiola L;Chabot PR;Cyr N;Arseneault G;Legault P;Omichinski JG
p65 是转录调节蛋白 NF-κB 家族的成员，作为 p65-p50 异二聚体的激活成分。通过其酸性反式激活结构域 (TAD)，p65 能够与几种不同的转录调节蛋白形成相互作用，包括 TFIIB、TFIIH、CREB 结合蛋白 (CBP)/p300 和 TAFII31。与其他酸性 TAD 一样，p65 TAD 包含两个子结构域（p65TA1 和 p65TA2），它们根据靶基因与不同的调控因子相互作用。尽管 p65TA1 在控制众多 NF-κB 靶基因方面发挥着重要作用，但 p65TA1 与靶转录调控因子结合的高分辨率结构尚不存在。在这项工作中，我们表征了 p65TA1 与两个因子（TFIIH 的 Tfb1/p62 亚基和 CBP 的 KIX 结构域）的相互作用。在这些复合物中，p65TA1 转变为螺旋构象，其中包括其特征性 ΦXXΦΦ 基序（Φ = 疏水性氨基酸）。结构和功能研究表明，两个结合界面主要由 ΦXXΦΦ 基序内的三个疏水氨基酸稳定，这些残基对其激活转录的能力也至关重要。总而言之，这些结果提供了 p65TA1 如何能够结合激活 NF-κB 靶基因所需的不同转录调节因子的原子水平描述。
p65 is a member of the NF-κB family of transcriptional regulatory proteins that functions as the activating component of the p65–p50 heterodimer. Through its acidic transactivation domain (TAD), p65 has the capacity to form interactions with several different transcriptional regulatory proteins, including TFIIB, TFIIH, CREB-binding protein (CBP)/p300 and TAFII31. Like other acidic TADs, the p65 TAD contains two subdomains (p65TA1 and p65TA2) that interact with different regulatory factors depending on the target gene. Despite its role in controlling numerous NF-κB target genes, there are no high-resolution structures of p65TA1 bound to a target transcriptional regulatory factor. In this work, we characterize the interaction of p65TA1 with two factors, the Tfb1/p62 subunit of TFIIH and the KIX domain of CBP. In these complexes, p65TA1 transitions into a helical conformation that includes its characteristic ΦXXΦΦ motif (Φ = hydrophobic amino acid). Structural and functional studies demonstrate that the two binding interfaces are primarily stabilized by three hydrophobic amino acids within the ΦXXΦΦ motif and these residues are also crucial to its ability to activate transcription. Taken together, the results provide an atomic level description of how p65TA1 is able to bind different transcriptional regulatory factors needed to activate NF-κB target genes.