A FluoPol-ABPP PAD2 high-throughput screen identifies the first calcium site inhibitor targeting the PADs.
Department of Biochemistry and Molecular Pharmacology
Biochemistry | Enzymes and Coenzymes | Medicinal-Pharmaceutical Chemistry | Therapeutics
The protein arginine deiminases (PADs) catalyze the post-translational hydrolysis of peptidyl-arginine to form peptidyl-citrulline in a process termed deimination or citrullination. PADs likely play a role in the progression of a range of disease states because dysregulated PAD activity is observed in a host of inflammatory diseases and cancer. For example, recent studies have shown that PAD2 activates ERalpha target gene expression in breast cancer cells by citrullinating histone H3 at ER target promoters. To date, all known PAD inhibitors bind directly to the enzyme active site. PADs, however, also require calcium ions to drive a conformational change between the inactive apo-state and the fully active calcium bound holoenzyme, suggesting that it would be possible to identify inhibitors that bind the apoenzyme and prevent this conformational change. As such, we set out to develop a screen that can identify PAD2 inhibitors that bind to either the apo or calcium bound form of PAD2. Herein, we provide definitive proof of concept for this approach and report the first PAD inhibitor, ruthenium red (Ki of 17 muM), to preferentially bind the apoenzyme.
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Citation: ACS Chem Biol. 2014 Apr 18;9(4):913-21. doi: 10.1021/cb400841k. Epub 2014 Jan 27. Link to article on publisher's site
Lewallen, Daniel M.; Bicker, Kevin L.; Madoux, Franck; Chase, Peter; Anguish, Lynne; Coonrod, Scott; Hodder, Peter; and Thompson, Paul R., "A FluoPol-ABPP PAD2 high-throughput screen identifies the first calcium site inhibitor targeting the PADs." (2014). Thompson Lab Publications. 16.