Chemicals and antibody. Celastrol was ordered from MedChemExpress under the item number HY-13067. Antibodies against ezrin, ezrin pT567 and α-tubulin (DM1A) were purchased from Cell Signaling Technology. Antibodies against ROCK2 and ROCK2 (phospho S1366) were purchased from Abcam. Anti-GFP antibodies were purchased from Santa Cruz Biotechnology. Anti-FLAG-tag (M2) antibody was from Sigma. plasmids. The development of bacterial expression vectors containing human ezrin fused to histidine was described previously 61. EGFP-tagged ezrin plasmids was produced as described before 62. PCR amplified ROCK2 cDNA was cloned into the 3× FLAG-Myc-CMV-24 vector (Sigma) by BamHI and RcoRI digestion. The mutanted of ezrin and ROCK2 were constructed by Fast Mutagenesis Kit (Vazyme Biotech). All plasmids were verified by sequencing (Tsingke Biological Tech). cell culture and transfection. MHCC97H was a gift from Professor Yong Chen (Fourth Military Medical University) 20. HepG2 and HEK293T cells were from American Type Culture Collection (ATCC). Huh7 cells were from National Infrastructure of Cell Line Resource. The cells were incubated according to ATCC instruction. Cells were transfected using conventional calcium phosphate method or the Lipofectamine 3,000 (Invitrogen) according to manufacturer's instructions. Determination of cell viability (MTS assay). Celastrol cytotoxicity was assessed with the use of a CellTiter 96 AQueous One Solution Cell Proliferation Assay (Promega), which is a form of the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay. Cells (5,000 cells/well) were plated in 96-well plates, treated with various concentrations of celastrol for 24 h. After celastrol treatment, cell viability was determined by adding a small amount of the One Solution Reagent directly to culture wells, incubating for 3 h and then recording the absorbance at 490 nm with a 96-well plate reader. Wound healing assay. MHCC97H, HepG2 or Huh7 cells with logarithmic growth phases, was cultivated in 12 orifices with 5 × 10 5 cells density. Each group has three replicates. After a starvation of 6 h in serum-free medium, 10 μl Tip was taken to vertical scratch "#" glyph at the bottom of the culture plate. The floating cells were washed off with PBS and the celastrol was dissolved in medium supplemented with 20% FBS. Samples were photographed at 0 h, 4 h and 8 h. Image J software was used to measure and compare the effects of celastrol on cell migration. Single cell tracking assay. The cell migration by single cell tracking assay was performed as previously described 32. Briefly, MHCC97H cells were laid in a Silian dish. After stabilized, the cells were starved with Opti-MEM for 6 h, and then cultured in DMEM containing 20% FBS. The movement track of 10 single-cells in each field of view were recorded by microscope for 6 h, with 10 min interval at once.