(A) HeLa cells were pretreated by vehicle (DMSO) or 100 μM MDL28170 for 1 hr and then left uninfected or infected with the M90T strain or the mxiD mutant for 2 hr. Immunoblot analysis were performed using anti-Capns1 (Calpain small subunit 1), -calpastatin, -SUMO1, -SUMO2/3 and -tubulin antibodies. The 18 kDa truncated Capns1 fragment is indicated by an arrow. (B) HeLa cells were treated with control siRNA (siScr) or Capns1 siRNA and then left uninfected or infected with the M90T strain or the mxiD mutant for 2 hr. Immunoblot analysis were performed using anti-Capns1, -SUMO1, -SUMO2/3 and -tubulin antibodies. (C) Capns1+/+ (WT) or Capns1−/− (KO) MEFs were uninfected or infected with the M90T strain or the mxiD mutant for 2 hr. Immunoblot analysis was performed using anti-SUMO1, -SUMO2/3, and -tubulin antibodies.