Fig. 7.

Rapid (<300 ms) and strong Src activation (red/yellow spots) co-localizes with regions of large microtubule deformation (white arrows). A local stress was applied to integrins using a 4-μm magnetic bead (17.5 Pa for 3 s step) and Src activation was measured by CFP-YFP Src FRET. Then an oscillatory stress (17.5 Pa at 0.3 Hz) was applied for~10 s and microtubule deformation was quantified by tracking mCherry tubulin displacements induced by stress. For clarity, microtubule displacements <15 nm were omitted. Blue circle, bead–cell contact area (~6 μm²); blue arrow, bead movement direction; N = nucleus. The focal plane was ~1.5 μm above the cell base. Three other cells showed similar behaviors. 80% of strong Src activation co-localizes with regions of large microtubule deformation (>15 nm). In contrast, only ~10% of strong Src activation co-localizes with regions of large F-actin deformation.⁵⁰ Reproduced from ref. 89 with permission.