Fig. 3.

Streptococcus-induced ubiquitination of pro-IL-1β occurs independently of SLO-mediated inflammasome signaling. a Primed macrophages of different genotypes were infected with wild type (wt) or Δslo Group A Streptococcus (GAS), as indicated. The Nlrp3 inflammasome-activating toxin Nigericin (Nig) was used as a control. Supernatants were assessed for IL-1β by ELISA. b Different genotype macrophages were primed and infected with wt or Δslo GAS. IL-1β was precipitated from cell lysates and ubiquitin (Ub) and (pro-)IL-1β were assessed by immunoblot. c B6 macrophages were primed or primed and infected or treated with Nig, as indicated, in the presence or absence of KCl and IL-1β in the supernatant was assessed by ELISA. d B6 macrophages were primed or primed and infected, as indicated, in the presence or absence of KCl and IL-1β was precipitated from cell lysates and ubiquitin (Ub) and (pro-)IL-1β were assessed by immunoblot. Graphs show means plus SD for triplicate samples and are representatives of at least 3 independent experiments. Blots show 1 representative of 3 independent experiments.