Department of Pathology and Laboratory Medicine, Robert Larner, M.D. College of Medicine University of Vermont, 149 Beaumont Avenue, Burlington, VT, 05405, USA.
Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA, 02215, USA.
Nat Commun. 2018 Oct 30;9(1):4522. doi: 10.1038/s41467-018-06790-1.
The Src kinase controls aspects of cell biology and its activity is regulated by intramolecular structural changes induced by protein interactions and tyrosine phosphorylation. Recent studies indicate that Src is additionally regulated by redox-dependent mechanisms, involving oxidative modification(s) of cysteines within the Src protein, although the nature and molecular-level impact of Src cysteine oxidation are unknown. Using a combination of biochemical and cell-based studies, we establish the critical importance of two Src cysteine residues, Cys-185 and Cys-277, as targets for HO-mediated sulfenylation (Cys-SOH) in redox-dependent kinase activation in response to NADPH oxidase-dependent signaling. Molecular dynamics and metadynamics simulations reveal the structural impact of sulfenylation of these cysteines, indicating that Cys-277-SOH enables solvent exposure of Tyr-416 to promote its (auto)phosphorylation, and that Cys-185-SOH destabilizes pTyr-527 binding to the SH2 domain. These redox-dependent Src activation mechanisms offer opportunities for development of Src-selective inhibitors in treatment of diseases where Src is aberrantly activated.
Src 激酶控制着细胞生物学的各个方面，其活性受到蛋白质相互作用和酪氨酸磷酸化诱导的分子内结构变化的调节。最近的研究表明，Src 还受到依赖于氧化还原的机制的调节，涉及 Src 蛋白内半胱氨酸的氧化修饰，尽管 Src 半胱氨酸氧化的性质和分子水平的影响尚不清楚。本研究采用生化和基于细胞的研究相结合的方法，确定了 Src 两个半胱氨酸残基 Cys-185 和 Cys-277 作为 HO 介导的半胱氨酸亚磺酰化（Cys-SOH）的靶标在 NADPH 氧化酶依赖性信号转导中对依赖于氧化还原的激酶激活的重要性。分子动力学和元动力学模拟揭示了这些半胱氨酸亚磺酰化的结构影响，表明 Cys-277-SOH 使 Tyr-416 能够暴露于溶剂中，从而促进其（自身）磷酸化，并且 Cys-185-SOH 使 pTyr-527 与 SH2 结构域的结合不稳定。这些依赖于氧化还原的 Src 激活机制为开发 Src 选择性抑制剂治疗Src 异常激活的疾病提供了机会。
