Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA.
Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, USA; Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, USA.
J Biol Chem. 2021 Jan-Jun;296:100311. doi: 10.1016/j.jbc.2021.100311. Epub 2021 Jan 19.
ZAP-70 is a tyrosine kinase essential for T cell immune responses. Upon engagement of the T cell receptor (TCR), ZAP-70 is recruited to the specialized plasma membrane domains, becomes activated, and is released to phosphorylate its laterally segregated targets. A shift in ZAP-70 distribution at the plasma membrane is recognized as a critical step in TCR signal transduction and amplification. However, the molecular mechanism supporting stimulation-dependent plasma membrane compartmentalization of ZAP-70 remains poorly understood. In this study, we identified previously uncharacterized lipidation (S-acylation) of ZAP-70 using Acyl-Biotin Exchange assay, a technique that selectively captures S-acylated proteins. We found that this posttranslational modification of ZAP-70 is dispensable for its enzymatic activity. However, the lipidation-deficient mutant of ZAP-70 failed to propagate the TCR pathway suggesting that S-acylation is essential for ZAP-70 interaction with its protein substrates. The kinetics of ZAP-70 S-acylation were consistent with TCR signaling events indicating that agonist-induced S-acylation is a part of the signaling mechanism controlling T cell activation and function. Taken together, our results suggest that TCR-induced S-acylation of ZAP-70 can serve as a critical regulator of T cell-mediated immunity.
ZAP-70 是 T 细胞免疫反应所必需的一种酪氨酸激酶。在 T 细胞受体 (TCR) 结合后，ZAP-70 被募集到专门的质膜域，被激活，并被释放以磷酸化其侧向分离的靶标。ZAP-70 在质膜上的分布转移被认为是 TCR 信号转导和放大的关键步骤。然而，支持刺激依赖性 ZAP-70 质膜区室化的分子机制仍知之甚少。在这项研究中，我们使用酰基辅酶 A 交换测定法（一种选择性捕获 S-酰化蛋白的技术）鉴定了 ZAP-70 以前未表征的脂化（S-酰化）。我们发现，ZAP-70 的这种翻译后修饰对于其酶活性不是必需的。然而，ZAP-70 的脂质缺陷突变体未能传播 TCR 途径，这表明 S-酰化对于 ZAP-70 与其蛋白质底物的相互作用是必不可少的。ZAP-70 的 S-酰化动力学与 TCR 信号事件一致，表明激动剂诱导的 S-酰化是控制 T 细胞激活和功能的信号机制的一部分。总之，我们的结果表明，TCR 诱导的 ZAP-70 的 S-酰化可以作为 T 细胞介导免疫的关键调节剂。
