Dynamics of Actin Stress Fibers and Focal Adhesions during Slow Migration in Swiss 3T3 Fibroblasts: Intracellular Mechanism of Cell Turning

Figure 7

Dynamics of actin SFs together with FAs. The analysis here is based on the same data presented in Figures 3, 4(a)–4(d) and 5. (a) Merged images of GFP-actin and RFP-zyxin. (b) The time-lapse montages of GFP-actin and RFP-zyxin were built from the boxed area B in panel (a) (region F). The cell edge extracted from the montage of GFP-actin is indicated by a dotted line in the montage of RFP-zyxin. The edge of the cell moved gradually in the upper direction, which indicated that the cell protruded. The montage of RFP-zyxin demonstrated that new FAs (orange, yellow, green, light blue, and blue arrowheads) were formed one after another at an anterior position to the preexisting FAs (red arrowheads). The FAs in the region F formed simultaneously with SFs (thick bundled-like filaments in the montage of GFP-actin) and disappeared simultaneously with the disappearance of the SFs. (c) Time-lapse montages were built from the boxed area C in panel (a) (region L). From the montage of GFP-actin, the cell did not protrude. Yellow arrowheads in the montage of RFP-zyxin showed that a small FA appeared close to the cell edge and its area became gradually larger. As for the case in (c), an SF was observed vertically from the position of the FA and intersecting SF connections were also observed (red arrowheads in the montage of GFP-actin). (d) Time-lapse montages were built from the boxed area D in panel (a) (region R). From the montages of GFP-actin and RFP-zyxin, we could recognize the relocating FA connected to a bundle-like SF with a contractile movement.

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