Fig. 3.

Cholesterol depletion promotes formation of actin stress fibers. Double labeling for F-actin (phalloidin-Alexa 488 nm) and filipin (405 nm). A: Untreated preparations show typical stress fiber organization dotted by lipid rafts. B: About 1 h of incubation with MβCD results in dissolution of filipin⁺ puncta and upregulation of phalloidin-actin fluorescence. C: Saturated 1:10 admixture of cholesterol (1 mM) and MβCD (10 mM) increased the number of filipin puncta. D, E: Averaged data for experiments shown in A–C (N = 3–4). ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, and ∗∗∗∗P < 0.0001. The scale bar represents 20 μm.