<div><p>(<b>A</b>) Propagation of a constriction ring (arrow) for an HT-1080 migrating in synthetic ECM (220 Pa, 1000 μM CRGDS; 10 min / frame, see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081689#pone.0081689.s014" target="_blank">Movie S3</a>). (<b>B</b>) Propagation of a constriction ring (arrow) for an HT-1080 migrating in collagen (1.7 mg/mL; 15 min./frame, see also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081689#pone.0081689.s020" target="_blank">Movie S9</a>). Scale bars = 25 μm.</p>
<p>(<b>C</b>-<b>G</b>) Z-projected immunofluorescence images illustrating myosin IIb expression for an HT-1080 in synthetic ECM (220 Pa, 1000 μM CRGDS): (<b>C</b>) Overlay image illustrating myosin IIb (green), counterstained with TRITC-conjugated phalloidin (F-actin, red) and DAPI (nucleus, blue). Single channel images (grayscale) illustrate (<b>D</b>) F-actin and (<b>E</b>) Myosin IIb. Profile plots generated using ImageJ “Interactive 3D Surface Plot” function (“Spectrum” intensity scale, projection for middle 3 planes) illustrate (<b>F</b>) F-actin and (<b>G</b>) Myosin IIb. Two consecutive single plane images (grayscale) illustrate (<b>H</b>) F-actin and (<b>I</b>) Myosin IIb.</p></div