a, Immunoblot analysis of HeLa cells infected for 5 hours with L. monocytogenes. b, Immunoblot analysis of HeLa cells transfected with a SUMO1 expression vector or a control plasmid and treated with 3 nM LLO. c, Luciferase activities, in response to hTGF-β1, in 293FT cells transfected with a SMAD reporter plasmid and infected with wild-type (WT) or Δhly L. monocytogenes (n=3; error bars, s.d.). d, Immunoblot analysis of HeLa cells transfected with an expression vector for SUMO1, SUMO2 or the corresponding empty vector as a control. e, Number of intracellular bacteria recovered from HeLa cells transfected as in d and infected with L. monocytogenes for 7 hours (n=3; error bars, s.d.). f, Quantification of Ubc9 levels in liver homogenates from C57Bl/6J mice infected with L. monocytogenes (n=8 animals per group; error bars, s.d.; *, P<0.01).