凋亡信号调节激酶1(ASK1)是一种至关重要的应激传感器,引导细胞凋亡,分化,和衰老通过p38和JNK信号通路。ASK1失调与癌症和炎症有关,心血管,和神经退行性疾病,在其他人中。然而,我们对ASK1调控的潜在结构机制的了解有限,这阻碍了我们将MAP3K蛋白家族的这一成员用于开发针对这些疾病的治疗干预措施的能力.然而,作为多域Ser/Thr蛋白激酶,ASK1由涉及二聚化和与其他几种蛋白质相互作用的复杂机制调节。包括硫氧还蛋白1(TRX1)。因此,本研究旨在使用几种生物物理技术在结构上表征ASK1及其与TRX1的复合物。如低温EM分析所示,在接近其活动形式的状态下,ASK1是一种紧凑且不对称的二聚体,这使得广泛的域间和链间相互作用成为可能。这些相互作用稳定ASK1激酶结构域的活性构象。反过来,TRX1充当ASK1的负变构效应子,修饰TRX1结合域的结构并改变其与四肽重复域的相互作用。因此,TRX1减少了对激酶结构域的激活区段的访问。总的来说,我们的发现不仅阐明了ASK1二聚化和域间接触的作用,而且还提供了对其调节的关键机制见解,从而突出了ASK1蛋白-蛋白相互作用作为抗炎治疗靶标的潜力。
Apoptosis signal-regulating kinase 1 (
ASK1) is a crucial stress sensor, directing cells toward apoptosis, differentiation, and senescence via the p38 and JNK signaling pathways.
ASK1 dysregulation has been associated with cancer and inflammatory, cardiovascular, and neurodegenerative diseases, among others. However, our limited knowledge of the underlying structural mechanism of
ASK1 regulation hampers our ability to target this member of the MAP3K protein family towards developing therapeutic interventions for these disorders. Nevertheless, as a multidomain Ser/Thr protein kinase, ASK1 is regulated by a complex mechanism involving dimerization and interactions with several other proteins, including thioredoxin 1 (TRX1). Thus, the present study aims at structurally characterizing ASK1 and its complex with TRX1 using several biophysical techniques. As shown by cryo-EM analysis, in a state close to its active form, ASK1 is a compact and asymmetric dimer, which enables extensive interdomain and interchain interactions. These interactions stabilize the active conformation of the
ASK1 kinase domain. In turn, TRX1 functions as a negative allosteric effector of
ASK1, modifying the structure of the TRX1-binding domain and changing its interaction with the tetratricopeptide repeats domain. Consequently, TRX1 reduces access to the activation segment of the kinase domain. Overall, our findings not only clarify the role of ASK1 dimerization and inter-domain contacts but also provide key mechanistic insights into its regulation, thereby highlighting the potential of ASK1 protein-protein interactions as targets for anti-inflammatory therapy.