Targeted Protein Degradation Assay Services

Targeted protein degraders comprise a class of molecules that induce protein degradation of a specific disease-causing protein by the cell's ubiquitin-proteasome pathway. In the past few years, various molecule classes have evolved including PROTACs (Proteolysis-targeting chimeras), molecular glue, selective receptor degraders, and cerebron-binding molecules, to name a few.

All protein degraders have in common a drug discovery approach that is different from the classic inhibition of the function of a target. The discovery of new molecules facilitating targeted protein degradation requires a set of assays to investigate the binding of a drug to target, the structure of the drug-target complex as well as the degradation of the target from the cell. 

Protein Degradation via PROTACs

A PROTAC molecule consists of three parts – the target binding head and a E3 ligase interacting part which are connected via a linker. The PROTAC draws the target into a ternary complex with the ubiquitination complex tagging the target for degradation via proteasomes.

The PROTAC draws the target into a ternary complex with the ubiquitination complex tagging the target degradation via proteasomes.

Workflow for the discovery of new targeted protein degradation molecules.

  1. The binding affinity of new compounds to the target and the ligase can be tested via microscale thermophoresis (MST), thermal shift assay, or fluorescent assays such as AlphaScreen or fluorescent polarization assays. More than 2000 assays against a variety of targets are established at Reaction Biology and readily available for screening.
  1. Cellular NanoBRET target engagement assays can determine the binding affinity of the compound to the target and the ligase in the physiologic environment of intact cells.
  1. Western blotting of lysates of treated cells is used to test whether the drug treatment actually leads to the degradation of the target in the cellular setup.
  1. SPR is used to determine the kinetics of the binding event, whereas ITC (isothermal titration calorimetry) is performed to identify the thermodynamic binding parameters. Both methods will determine the mechanism of action (MOA) of the drug.
  1. Successful lead candidates designated for treatment of oncology are then advanced to functional testing in tumor cell lines for their anti-proliferative or anti-metastatic potency and subsequently tested in mouse tumor models.
Workflow for the discovery of new targeted protein degradation molecules including PROTACs

We are currently talking to biotech and pharma companies to perform fee-for-service, shared-cost collaboration or FTE-based work for the development of new protein degradation molecules. Please reach out to our Business Development Team to discuss options for supporting your drug discovery program.