Abstract
Innate immune signaling relies heavily on phosphorylation cascades to mount effective immune responses. Although traditional innate immune signaling cascades following TLR4 stimulation have been investigated through a temporally quantitative phosphoproteomic lens, far fewer studies have applied these methods to distinct signaling following the inflammasome trigger leading to IL-1β release. Here, we conducted time-resolved phosphoproteomic profiling to investigate kinase signaling downstream of the inflammasome trigger nigericin. We found that nigericin induces rapid and potent alterations in the phosphorylation landscape where immune-related signaling, mitogen-activated protein kinases (MAPKs), and PKC signaling are prevalent. We also found significant evidence of phospho-modified metabolic cascades, suggesting that phosphosignaling plays a role in previously described immunometabolic regulation. These signaling events preceded robust phosphorylation of DNA damage and chromatin reorganization proteins before pyroptotic rupture. Lastly, by performing temporal clustering of phospho-dynamics, we revealed novel ontology-level shifts in phosphosignaling cascades following nigericin treatment that highlight abrupt changes in cellular behavior during early and late intracellular inflammatory events. SUMMARY: Protein phosphorylation is critical to convey innate immune signaling information to specific effector arms of the cellular immune response. This study focuses on characterizing phosphoproteomic alterations stemming from the inflammasome trigger nigericin. By gaining a deeper understanding of global kinase phosphodynamics in response to inflammasome activation, we aim to identify novel pharmacological targets to treat chronic inflammatory diseases driven by inflammasome-dependent IL-1β release.