Novel interaction interfaces mediate the interaction between the NEIL1 DNA glycosylase and mitochondrial transcription factor A.
Novel interaction interfaces mediate the interaction between the NEIL1 DNA glycosylase and mitochondrial transcription factor A.
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DOI：
10.3389/fcell.2022.893806
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发表时间：
2022
影响因子：
5.5
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中科院分区：
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人类线粒体DNA （mtDNA）的维护对于正常的细胞功能至关重要，因为mtDNA的损伤如果不进行修复，可能导致各种各样的病理。在已确定的参与线粒体内DNA修复的途径中，碱基切除修复（BER）是研究最广泛的。蛋白质-蛋白质相互作用推动了成功完成该途径所需的一步一步的协调，并且对于与参与基因组维持的其他线粒体因子的串扰非常重要。人类NEIL1是七种DNA糖基酶之一，可以在核室和线粒体室中启动BER。在目前的工作中，我们仔细研究了NEIL1和线粒体转录因子A （TFAM）之间的相互作用，TFAM是mtDNA代谢的各个方面所必需的蛋白质。我们首次注意到NEIL1的N端和C端结构域与TFAM相互作用，揭示了一个独特的NEIL1蛋白结合界面。从生物化学角度观察，这两种蛋白质之间的相互作用似乎是短暂的，在低盐浓度下最明显。DNA（或RNA）的存在也对两种蛋白质之间的相互作用产生积极影响，摩尔质量估计表明，在较高的盐浓度下，复体形成需要双链DNA。氢氘交换质谱数据显示，这两种蛋白质在DNA结合时交换较少的氘，表明相互作用，并且在TFAM-DNA复合体中添加NEIL1改变了相互作用的格局。在正常细胞条件下，TFAM的转录活性似乎独立于NEIL1的表达，然而，在存在DNA损伤的情况下，我们观察到在缺乏NEIL1的情况下，TFAM转录的线粒体基因的mRNA表达显著降低。总的来说，我们的数据表明NEIL1和TFAM之间的相互作用可以通过局部环境（如盐浓度、蛋白质可用性、核酸的存在以及DNA损伤的存在）来调节。
The maintenance of human mitochondrial DNA (mtDNA) is critical for proper cellular function as damage to mtDNA, if left unrepaired, can lead to a diverse array of pathologies. Of the pathways identified to participate in DNA repair within the mitochondria, base excision repair (BER) is the most extensively studied. Protein-protein interactions drive the step-by-step coordination required for the successful completion of this pathway and are important for crosstalk with other mitochondrial factors involved in genome maintenance. Human NEIL1 is one of seven DNA glycosylases that initiates BER in both the nuclear and mitochondrial compartments. In the current work, we scrutinized the interaction between NEIL1 and mitochondrial transcription factor A (TFAM), a protein that is essential for various aspects of mtDNA metabolism. We note, for the first time, that both the N- and C- terminal domains of NEIL1 interact with TFAM revealing a unique NEIL1 protein-binding interface. The interaction between the two proteins, as observed biochemically, appears to be transient and is most apparent at concentrations of low salt. The presence of DNA (or RNA) also positively influences the interaction between the two proteins, and molar mass estimates indicate that duplex DNA is required for complex formation at higher salt concentrations. Hydrogen deuterium exchange mass spectrometry data reveal that both proteins exchange less deuterium upon DNA binding, indicative of an interaction, and the addition of NEIL1 to the TFAM-DNA complex alters the interaction landscape. The transcriptional activity of TFAM appears to be independent of NEIL1 expression under normal cellular conditions, however, in the presence of DNA damage, we observe a significant reduction in the mRNA expression of TFAM-transcribed mitochondrial genes in the absence of NEIL1. Overall, our data indicate that the interaction between NEIL1 and TFAM can be modulated by local environment such as salt concentrations, protein availability, the presence of nucleic acids, as well as the presence of DNA damage.