Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russian Federation.
Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russian Federation.
Elife. 2024 Sep 2;13:e96832. doi: 10.7554/eLife.96832.
BTB (bric-a-brack, Tramtrack, and broad complex) is a diverse group of protein-protein interaction domains found within metazoan proteins. Transcription factors contain a dimerizing BTB subtype with a characteristic N-terminal extension. The Tramtrack group (TTK) is a distinct type of BTB domain, which can multimerize. Single-particle cryo-EM microscopy revealed that the TTK-type BTB domains assemble into a hexameric structure consisting of three canonical BTB dimers connected through a previously uncharacterized interface. We demonstrated that the TTK-type BTB domains are found only in Arthropods and have undergone lineage-specific expansion in modern insects. The genome encodes 24 transcription factors with TTK-type BTB domains, whereas only four have non-TTK-type BTB domains. Yeast two-hybrid analysis revealed that the TTK-type BTB domains have an unusually broad potential for heteromeric associations presumably through a dimer-dimer interaction interface. Thus, the TTK-type BTB domains are a structurally and functionally distinct group of protein domains specific to Arthropodan transcription factors.
BTB（bric-a-brack、Tramtrack、和 broad complex）是真核生物蛋白内发现的一组多样化的蛋白-蛋白相互作用结构域。转录因子包含具有特征性 N 端延伸的二聚化 BTB 亚型。Tramtrack 结构域（TTK）是一种独特的 BTB 结构域，可以多聚化。单颗粒冷冻电镜显微镜揭示了 TTK 型 BTB 结构域组装成一个六聚体结构，由三个通过以前未表征的界面连接的典型 BTB 二聚体组成。我们证明了 TTK 型 BTB 结构域仅存在于节肢动物中，并且在现代昆虫中经历了谱系特异性扩张。基因组编码 24 个具有 TTK 型 BTB 结构域的转录因子，而仅有四个具有非 TTK 型 BTB 结构域。酵母双杂交分析表明，TTK 型 BTB 结构域具有异常广泛的异源二聚体相互作用的潜力，可能是通过二聚体-二聚体相互作用界面。因此，TTK 型 BTB 结构域是一种结构和功能上都不同于节肢动物转录因子的蛋白结构域。
