To identify the substrates of deubiquitinase USP13, we used a protein label-free quantitation technique, which involves mass spectrometry analysis of peptides from protein digests using liquid chromatography, to identify candidate substrates of USP13 that interact with it from co-immunoprecipitation of HEK293T cells and candidate substrates of USP13 that are upregulated by its overexpression in HEK293T cells, from the data sets of the full protein profile and protein-protein interactions.