Caspase-Glo 1 Inflammasome Assay
The Caspase-Glo 1 Inflammasome Assay is a homogeneous, bioluminescent method to selectively measure the activity of caspase-1, a member of the cysteine aspartic acid-specific protease (caspase) family and an essential component of the inflammasome. Inflammasomes are protein complexes induced by diverse inflammatory stimuli. Innate immune cells respond to pathogens and other danger signals with inflammasome formation and conversion of procaspase-1 zymogen into catalytically active caspase-1. Caspase-1 activation results in: 1) the processing and release of cytokines IL-1-beta and IL-18 and 2) pyroptosis, an immunogenic form of cell death. The Caspase-Glo 1 Inflammasome Assay provides a luminogenic caspase-1 substrate, Z-WHED-aminoluciferin, in a lytic reagent optimized for caspase-1 activity and luciferase activity. A single addition of this reagent results in cell lysis, substrate cleavage by caspase-1 and generation of light by a proprietary, thermostable, recombinant luciferase (Ultra-Glo Recombinant Luciferase). The coupled-enzyme system reaches a steady-state between caspase cleavage of the substrate and luciferase conversion of aminoluciferin. These simultaneous reactions generate a stable luminescent signal, which is proportional to caspase activity. Inclusion of the proteasome inhibitor MG-132 in the reagent eliminates nonspecific proteasome-mediated cleavage of the substrate, enabling sensitive measurement of caspase-1 activity.