The immune system uses the recognition of foreign nucleic acids and subsequent type I interferon production as a first line of defense in response to microbial invaders. Recent research has validated one key to this cascade, a unique cyclic dinucleotide – cGAMP. The enzyme cGAS produces this recently discovered molecular messenger. As an apoenzyme, cGAS is enzymatically inactive. However, upon binding to non-specific dsDNA, cGAS transitions to an active conformation producing cGAMP from ATP and GTP. Abnormal IFN induction occurs when self-DNA triggers unabated cGAMP production by cGAS, causing devastating autoimmune diseases such as Aicardi–Goutieres Syndrome (AGS), systemic lupus erythematosus (SLE), and Sjogren’s syndrome. Therefore, inhibiting cGAS is an emerging strategy to identify novel drugs for autoimmune diseases.
BellBrook Labs has developed a cGAS activity assay with fluorescence polarization (FP) and TR-FRET readouts based on the proven Transcreener® HTS platform. Identifying bona fide hits efficiently and effectively is a challenge in any small molecule drug discovery program. The Transcreener cGAS Assay is the only method available with direct detection of cGAMP. Alternative cGAMP detection assays use mass spec or measure depleted ATP with coupled assays making them prone to assay interference and generating false positives that require time-consuming counter-screens to triage. Transcreener’s sensitivity reduces the quantity of enzyme and substrate required saving valuable resources during screening. And while the assay’s flexibility and simplicity make it an excellent fit for HTS, there are also distinct advantages in SAR and MOA studies.
View the Previously Recorded Webinar from November, 2020!
In this webinar, we discuss:
- Sensitive detection of cGAS initial velocity in the presence of saturating ATP and GTP concentrations
- Providing overnight and reagent signal stability that provide flexibility in liquid handling
- Measuring accurate IC50 values
- Determining the inhibitor mechanism of action
- Kinetic studies such as residence-time determination