Bioorthogonal Reporters for Detecting and Profiling Protein Acetylation and Acylation

Protein acylation, exemplified by lysine acetylation, is a type of indispensable and widespread protein posttranslational modification in eukaryotes. Functional annotation of various lysine acetyltransferases (KATs) is critical to understanding their regulatory roles in abundant biological processes. Traditional radiometric and immunosorbent assays have found broad use in KAT study but have intrinsic limitations. Designing acyl-coenzyme A (CoA) reporter molecules bearing chemoselective chemical warhead groups as surrogates of the native cofactor acetyl-CoA for bioorthogonal labeling of KAT substrates has come into a technical innovation in recent years. This chemical biology platform equips molecular biologists with empowering tools in acyltransferase activity detection and substrate profiling. In the bioorthogonal labeling, protein substrates are first enzymatically modified with a functionalized acyl group. Subsequently, the chemical warhead on the acyl chain conjugates with either an imaging chromophore or an affinity handle or any other appropriate probes through an orthogonal chemical ligation. This bioorganic strategy reformats the chemically inert acetylation and acylation marks into a chemically maneuverable functionality and generates measurable signals without recourse to radioisotopes or antibodies. It offers ample opportunities for facile sensitive detection of KAT activity with temporal and spatial resolutions as well as allows for chemoproteomic profiling of protein acetylation pertaining to specific KATs of interest on the global scale. We reviewed here the past and current advances in bioorthogonal protein acylations and highlighted their wide-spectrum applications. We also discussed the design of other related acyl-CoA and CoA-based chemical probes and their deployment in illuminating protein acetylation and acylation biology.