Chemical Proteomic Profiling of the Histaminylation Proteome in Cancer Cells Unveils Uncharted Epigenetic Marks on Core Histones
Xingyu Ma, Anne A. Leaman, Zeng Lin, Huapeng Li, Zhengjun Cai, Qianyue Wang, Kaiwaan Dalal, Md Shahadat Hossain, Venkatesh P. Thirumalaikumar, Zhihong Wang, Valerie P. O’Brien, W. Andy Tao, Qingfei ZhengAbstract
Histamine is a key signaling molecule in pathophysiology that can exhibit significant regulatory roles in diverse health and disease states. Besides the well-studied noncovalent interactions between histamine and its receptors, protein histaminylation is a recently discovered mechanism of action through which histamine regulates cellular signaling pathways in a covalent modification manner. Histaminylation is an emerging protein post-translational modification (PTM), where an isopeptide bond is formed between the histamine primary amine and the γ-carboxyl group of glutamine through a transamidation reaction catalyzed by transglutaminase 2 (TGM2). However, due to the lack of efficient pan-specific antibodies targeting histaminylated glutamine, the histaminylation proteome in cells remains poorly explored. Here, we report the design and development of a novel Nτ-propargylated histamine (Nτ-PH) probe as well as its successful application in chemical proteomic profiling of the histaminylation proteome in cancer cells. Notably, new TGM2-catalyzed epigenetic marks on core histones, e.g., H2AX-Q84 and Q104 histaminylation, have been identified from cancer cells and verified. Lastly, the crosstalk between H2AX histaminylation and γH2AX formation was discovered in this study, suggesting that TGM2-mediated histaminylation plays a critical role in DNA damage responses.