Figure 2: Fiber tension before and after isolation.
(A) Pre-tension values of non-isolated fibers (“inward before isolation”) compared to isolated fibers deformed inward (“inward after isolation”) and outward (“outward after isolation”). Number of measured fibers for each case (n) is indicated, each fiber has been tested in at least two of the three conditions. For each boxplot, the central red line is the median, the edges of the box are the 25th and 75th percentiles and the whiskers (black dashed lines) extend to the most extreme data points not considered outliers. Inset shows a typical force-deformation curve of isolated fiber T(δ) where T is fiber tension and δ is fiber longitudinal elongation. This graph allows extracting the value of pre-tension T0: circles are the experimental values, red line is the linear trend of the data points and T0 is the value of T at zero-elongation, i.e. the y-intercept of the graph. (B) Fluorescence intensity profiles of the F-actin in non-isolated (∗∗upper graph) and isolated (∗lower graph) fibers of the cell shown in inset, stained with phalloidin-AlexaFluor568. Profiles are taken transversally to the fibers and averaged along the length (ROIs shown by boxes in the inset), bars show s.d. Fluorescence image was obtained by a maximal projection of a confocal stack, voxel size was 0.20 × 0.20 × 0.60 μm. Bar is 10 μm.
