Fig. 5: abLIM1 depletion impairs the interwoven cortical actin meshwork.

Pooled data are presented as mean ± s.d. Student’s t test: *P < 0.05; ***P < 0.001. a Typical scanning EM images to show different (dense, medium, or sparse) cortical actin density. RPE1 cells transfected for 48 h were treated with Triton X-100 to remove the plasma membranes for scanning EM. Cells close to confluency were used to reduce influences of blebbing or membrane protrusion on cortical actin morphology. The framed areas were magnified to show details. Arrows indicate long cortical actin fibers in the abLIM1-depleted cell. b Quantification results from three independent experiments, based on the criteria in (a). At least 20 cells were scored in each experiment and condition. c abL1-i1 efficiently depleted abLIM1 in U2OS cells. GAPDH served as loading control. d AFM images. Living U2OS cells transfected for 72 h were imaged with the Peak Force mode of AFM. The framed regions were scanned at higher resolutions. The spectrum indicates height information. Arrows indicate long cortical actin fibers in the abLIM1-depleted cell. Note that the finest structures of the cortex as seen in (a) were not resolved because the radius of the AFM probe was 10 nm. e Increased cortical stiffness in the abLIM1-depleted U2OS cells. Young’s modulus maps for the cells in (d) are shown. The average Young’s modulus in a 10 μm × 10 μm region over (white frames) or beside (green frames) the nucleus was quantified. 10 cells from three independent experiments were analyzed in each group