Host Cell Vimentin Restrains Toxoplasma gondii Invasion and Phosphorylation of Vimentin is Partially Regulated by Interaction with TgROP18

He, Cheng; Kong, Ling; Zhou, Lijuan; Xia, Jing; Wei, Haixia; Liu, Min; Peng, Hongjuan

To investigate the effects of T. gondii infection on vimentin reorganization, the ratios of soluble to insoluble vimentin, and total to phosphorylated vimentin were evaluated at different infection time points, based on western-blot signals. The solubility of vimentin decreased in host cells in the first 6h post-infection ( Figure 3A and B), and the decrease was statistically significant (one way ANOVA; Figure 3B ). Vimentin phosphorylation patterns in host cells infected with T. gondii for different amounts of time were determined by Phos-tag assays and western blotting. Vimentin phosphorylation levels were highest at 6h post-infection and subsequently decreased to, and were maintained at low levels compared with uninfected cells ( Figure 3C ). Vimentin total protein levels also appeared to be regulated by T. gondii infection at different time points ( Figure 3D ). These data suggest that the dynamic regulation of vimentin, including its solubility, phosphorylation, and expression levels, are regulated by T. gondii infection.