REDEFINING THE MECHANISM AND SPECIFICITY OF INFLAMMASOME REGULATION BY POPS

Inflammasomes are an innate immune surveillance system that monitors host cells for both pathogen invasion and cell damage. Upon activation, inflammasomes enter an all-or-nothing signaling cascade that culminates in the activation of Caspase-1, pyroptotic cell death and the release of Interleukin-1β and Interleukin-18, thus priming the adaptive immune system to respond to the detected crisis. The following document will focus on a set of inflammasome regulators known as Pyrin-Only Proteins (POPs) which work to prevent runaway AIM2/ASC inflammasome activation. There are three known POPs: POP1, POP2 and POP3, each with a unique function and ability to regulate different components of the inflammasome. I used several orthogonal assays to determine the behavior of the POPs on their own and in respect to the inflammasome including FRET assays to measure filamentation of PYDs, Electron microscopy to observe the POPs alone and in concert with other PYDs, fluorescence microscopy to observe the effect of POPs on filament formation in solution and cell based imaging experiments to observe the POPs effects on inflammasomes in cultured cells. Based on my results I was able to confirm my hypothesis that POP1 functions as a regulator of inflammasomes upstream of the ASC adaptor protein, POP2 is a regulator of ASC itself, and POP3 has the broadest activity as a pan inflammasome regulator