Department of Radiation Oncology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States.
Center for Cancer Metabolism, James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States.
J Proteome Res. 2024 Oct 4;23(10):4457-4466. doi: 10.1021/acs.jproteome.4c00409. Epub 2024 Aug 29.
Serotonylation has been identified as a novel protein posttranslational modification for decades, where an isopeptide bond is formed between the glutamine residue and serotonin through transamination. Transglutaminase 2 (also known as TGM2 or TGase2) was proven to act as the main "writer" enzyme for this PTM, and a number of key regulatory proteins (including small GTPases, fibronectin, fibrinogen, serotonin transporter, and histone H3) have been characterized as the substrates of serotonylation. However, due to the lack of pan-specific antibodies for serotonylated glutamine, the precise enrichment and proteomic profiling of serotonylation still remain challenging. In our previous research, we developed an aryldiazonium probe to specifically label protein serotonylation in a bioorthogonal manner, which depended on a pH-controlled chemoselective rapid azo-coupling reaction. Here, we report the application of a photoactive aryldiazonium-biotin probe for the global profiling of serotonylation proteome in cancer cells. Thus, over 1,000 serotonylated proteins were identified from HCT 116 cells, many of which are highly related to carcinogenesis. Moreover, a number of modification sites of these serotonylated proteins were determined, attributed to the successful application of our chemical proteomic approach. Overall, these findings provided new insights into the significant association between cellular protein serotonylation and cancer development, further suggesting that to target TGM2-mediated monoaminylation may serve as a promising strategy for cancer therapeutics.
几十年来，人们已经发现了一种新的蛋白质翻译后修饰——色氨酰化，即通过转氨基作用在谷氨酸残基和色氨酸之间形成异肽键。转谷氨酰胺酶 2（也称为 TGM2 或 TGase2）已被证明是这种 PTM 的主要“书写”酶，许多关键的调节蛋白（包括小 GTP 酶、纤维连接蛋白、纤维蛋白原、血清素转运体和组蛋白 H3）已被表征为色氨酰化的底物。然而，由于缺乏针对色氨酰化谷氨酸的通用特异性抗体，因此精确地富集和蛋白质组学分析色氨酰化仍然具有挑战性。在我们之前的研究中，我们开发了一种芳基重氮探针，以生物正交的方式特异性标记蛋白质色氨酰化，这依赖于 pH 控制的化学选择性快速偶联反应。在这里，我们报告了一种光活性芳基重氮-生物素探针在癌细胞中进行色氨酰化蛋白质组全局分析的应用。因此，从 HCT 116 细胞中鉴定出了超过 1000 种色氨酰化蛋白，其中许多与致癌作用高度相关。此外，还确定了这些色氨酰化蛋白的一些修饰位点，这归因于我们化学蛋白质组学方法的成功应用。总的来说，这些发现为细胞蛋白质色氨酰化与癌症发展之间的重要关联提供了新的见解，进一步表明靶向 TGM2 介导的单胺化可能是癌症治疗的一种有前途的策略。
