SUMO Monoclonal Antibodies Vary in Sensitivity, Specificity, and Ability to Detect Types of SUMO Conjugate

The post-translational modification, small ubiquitin-like modifier (SUMO) can be conjugated to target proteins to control its localization, activity, and protein interactions.  These SUMOylation events are critical for many cellular processes and have been shown to be misregulated in a multitude of diseases.  While the plethora of new SUMO tools has helped identify novel SUMO functions, there are concerns about the quality of these tools; specifically, the SUMO antibodies.  The recent work by Garvin et al. sought to perform a stringent investigation on a panel of SUMO antibodies to properly catalogue these tools for the SUMO research community.  At the time the study began there were over 90 SUMO antibodies, but the group narrowed them down to 9 SUMO1, 11 SUMO2/3, and 4 SUMO4 antibodies based on citation records.  Initial dot-blot tests were performed, and interestingly, there was a wide range in sensitivity; for example, some SUMO 2/3 antibodies (EPR300, SM23/496) showed almost no signal for recombinant SUMO 2/3 while others (12F3, 8A2) showed a strong, specific signal.  Additionally, specificity was also an issue as some SUMO 2/3 antibodies like 2H8 also detected recombinant SUMO 4.  During their studies the group also mapped approximate epitope regions for 18/24 antibodies.  The 24 SUMO antibodies were also analyzed via immunoblots, immunoprecipitation, and immunofluorescence assays in the presence of cell stress inducers, siRNA, and other stimulants that affect SUMOylation to identify the strengths and weakness of each antibody with respect to a given application.  Their summary radar plots were quite informative and will be a useful reference for the SUMO research community.  Cytoskeleton Inc’s SUMO-2/3 Antibody (Clone 12F3) (Cat. # ASM23) was identified as one of the best overall performers in the SUMO 2/3 category, while its SUMO 1 Antibody (Clone 5D8B16) (Cat. # ASM01) also performed well for specificity and sensitivity.