Cell cycle–dependent redox changes can mediate transient covalent modifications of cysteine thiols to modulate the activities of regulatory kinases and phosphatases. Our previously reported finding that protein cysteine oxidation is increased during mitosis relative to other cell cycle phases suggests that redox modifications could play prominent roles in regulating mitotic processes. The Aurora family of kinases and their downstream targets are key components of the cellular machinery that ensures the proper execution of mitosis and the accurate segregation of chromosomes to daughter cells. In this study, x-ray crystal structures of the Aurora A kinase domain delineate redox-sensitive cysteine residues that, upon covalent modification, can allosterically regulate kinase activity and oligomerization state. We showed in both Xenopus laevis egg extracts and mammalian cells that a conserved cysteine residue within the Aurora A activation loop is crucial for Aurora A activation by autophosphorylation. We further showed that covalent disulfide adducts of this residue promote autophosphorylation of the Aurora A kinase domain. These findings reveal a potential mechanistic link between Aurora A activation and changes in the intracellular redox state during mitosis and provide insights into how novel small-molecule inhibitors may be developed to target specific subpopulations of Aurora A.

细胞周期依赖性氧化还原变化可以介导半胱氨酸硫醇的瞬时共价修饰，以调节调节激酶和磷酸酶的活性。我们之前报道的发现，相对于其他细胞周期阶段，有丝分裂期间蛋白质半胱氨酸氧化增加，这表明氧化还原修饰可能在调节有丝分裂过程中发挥重要作用。Aurora 激酶家族及其下游靶标是细胞机制的关键组成部分，可确保有丝分裂的正确执行和染色体与子细胞的准确分离。在这项研究中，Aurora A 激酶结构域的 X 射线晶体结构描绘了氧化还原敏感的半胱氨酸残基，这些残基在共价修饰后可以变构调节激酶活性和寡聚化状态。我们在两个非洲爪蟾卵提取物和哺乳动物细胞发现，Aurora A 激活环内的保守半胱氨酸残基对于通过自磷酸化激活 Aurora A 至关重要。我们进一步表明，该残基的共价二硫化物加合物促进 Aurora A 激酶结构域的自磷酸化。这些发现揭示了 Aurora A 激活与有丝分裂期间细胞内氧化还原状态变化之间的潜在机制联系，并提供了有关如何开发新型小分子抑制剂以靶向 Aurora A 特定亚群的见解。