a, Comparison of SUMO-conjugated protein patterns from uninfected HeLa cells (−) or cells infected for 1, 3 or 5 hours with Listeria monocytogenes (L. m.) or Listeria innocua (L. i.). Whole cell lysates were analysed by immunoblotting experiments using antibodies specific for SUMO1 (upper panel) or SUMO2/3 (lower panel) isoforms. b, Analysis of SUMO1-conjugated protein patterns from uninfected HeLa cells (−) or cells infected for 3 hours with wild type (WT), ΔinlB or Δhly L. monocytogenes. c, Analysis of SUMO1 and SUMO2/3-conjugated protein patterns from HeLa cells incubated with 3 nM LLO for 20 min.