The PROTAC® Optimization Kit for BRD9-Cereblon Binding is designed for the testing and profiling of PROTACs® directed against BRD9 and Cereblon (CRBN). The BRD9 inhibitor BI-7273 is included as a control inhibitor of PROTAC® binding to BRD9. With this kit, three simple steps are required for the measurement of PROTAC® activity. First, the PROTAC® of interest is incubated with CRBN and BRD9. Next, acceptor beads are added, then donor beads, followed by reading of the Alpha-counts.

Illustration of the assay principle: a PROTAC® of interest or positive control dBRD9 (PROTAC®) interacts with both BRD9 and CRBN, bringing them in close proximity. BRD9 contains a GST tag, recognized by the GSH donor bead, while CRBN contains a FLAG tag that binds to the AlphaLISA™ acceptor bead conjugated with an anti-FLAG antibody. Upon excitation of the donor bead a singlet oxygen is generated by the donor bead, which excites the acceptor bead and emits light proportionally to the level of interaction. AlphaLISA™ immunoassays are a no-wash alternative to ELISA immunoassays. These assays are robust and ideal for a minimal hands-on approach.