FIGURE 5:
CA-MLCK and CA-ROCK2 regulate the viscoelastic properties of distinct SF subpopulations. (A) SF retraction analysis. Da: SF material destroyed by ablation; 2L: distance between SF ends over time (L is the retraction distance of a severed SF fragment); t: time. L-t curves for each stress fiber are fitted to a Kelvin-Voigt model to determine Lo, whose magnitude correlates with the SF’s dissipated elastic energy, and τ, the viscoelastic time constant, which reflects the ratio of viscosity to elasticity. (B) Lo and τ values of peripheral SF ablation for U2OS CA-ROCK2 and CA-MLCK cells cultured in the presence and absence of doxycycline (n = 21, 32 for U2OS CA-ROCK2, n = 42, 47 for U2OS CA-MLCK). (C) Lo and τ values of central SF ablation for U2OS CA-ROCK2 and CA-MLCK cells cultured in the presence and absence of doxycycline (n = 49, 51 for U2OS CA-ROCK 2, n = 22, 19 for U2OS CA-MLCK). Boxes represent 25th and 75th percentiles; whiskers represent 10th and 90th percentiles. Cross represents the mean of the distribution. Statistical differences calculated using Mann-Whitney (*p < 0.005, **p < 0.0005). Scale bars = 10 µm.