Protein Extraction and Western Blot Analysis

Whole cell lysates were obtained by re-suspending cell pellets in RIPA buffer (50 mM Tris pH7.4, 150 mMNaCl, 1% Triton X-100) with freshly added protease inhibitor (Roche) as previously described (Fan et al., 2020 (link)). Nuclear proteins were extracted using the NE-PER Kit (Pierce) following manufacturer’s recommendation (Mao et al., 2020a (link)). Western blot analyses were performed with anti-MRTF-A (Santa Cruz, sc-32909), anti-SRF (Cell Signaling Technology, 5147), anti-α-tubulin (Sigma, T6074), anti-Lamin A/C (Proteintech, 10298-1), anti-α-SMA (Abcam, ab5694), and anti-β-actin (Sigma, A1978). For densitometrical quantification, densities of target proteins were normalized to those of β-actin as previously described (Lv et al., 2020 (link); Wu et al., 2020 (link)). Data are expressed as relative protein levels compared to the control group which is arbitrarily set as 1.