Mining the active proteome in plant science and biotechnology.

Protein activity is essential functional information, yet difficult to predict from transcript or protein data. Activity-based protein profiling (ABPP) displays active proteins in proteomes using small molecule probes that irreversibly label proteins in their active state. Here, we review proof-of-concept ABPP studies in plant science. These studies displayed activities of dozens of plant cysteine proteases, lipases, methylesterases and the proteasome. ABPP in plants revealed differential protein activities in development and immunity and uncovered striking selectivity of pathogen-derived inhibitors and unexpected targets of commercial inhibitors. The unique, high-content information of ABPP and the robustness and simplicity of the assays will make ABPP a powerful tool in future plant science and biotechnology.