Cytoskeletal regulation by ECM dimensionality. (A) Actin (green) stress fibers (arrows) extend from the leading to the trailing edge, whereas stabilized acetylated tubulin (red) is tightly compacted toward the front of the cell. (B) Cells in 3D matrix (blue) show high levels of stabilized Glu-tubulin (green) directed toward the leading edge, which contains mostly Tyr-tubulin (red). The graph shows the Glu/Tyr tubulin ratio in 2D, 3D, and 1D. (C) After blebbistatin treatment, Glu-tubulin remains concentrated in an axonlike structure (arrowheads) polarized along the matrix, whereas nocodazole disrupts this architecture. (D) Comparison of effects of blebbistatin (Bleb) and nocodazole (Noc) on cell migration in 2D, 3D, and 1D conditions. (E) Summary of the effects of ECM topography/dimensionality on cell morphology and migration. Asterisks indicate centrosomes. (B and D) *, P < 0.05 versus 2D. Error bars indicate SEM. Bars, 10 µm.