 | Figure 5
Nature Neuroscience
- 9, 1274 - 1283 (2006)
Published online: 3 September 2006; | doi:10.1038/nn1762
Focal adhesion kinase signaling at sites of integrin-mediated adhesion controls axon pathfindingEstuardo Robles & Timothy M Gomez | | | | Figure 5. FAK promotes substratum-dependent growth cone turning.
(a) A merged image (two time points) of a GFP-expressing growth cone on laminin (blue), before (red, t = 0 min) and after (green, t = 20 min) a repulsive turn away from the tenascin-coated region. (b,c) Time-lapse images of the growth cone in a at indicated times. Note that the lamellipodium indicated by the arrow labeled 'D' extends onto laminin and is stable, whereas the lamellipodium indicated by the arrow labeled 'E' extends onto tenascin and is retracted. (d,e) Kymographs from growth cone regions contacting laminin or tenascin sampled along lines indicated by labeled arrows in b. Red line, location of laminin-tenascin boundary. (f) Average size of lamellipodial extensions and retractions from growth cones turning at laminin-tenascin borders. n = 7 growth cones. (g,h) Fluorescence images of a fixed growth cone at the laminin-tenascin boundary stained for F-actin (g) and pY397-FAK (h). Arrowheads, pY397-FAK puncta in lamellipodia on laminin. (i,j) Quantification of pY397-FAK immunofluorescence intensity and puncta density in lamellipodia extended onto laminin and tenascin (n = 25 growth cones). (k,l) A GFP-FRNK–expressing spinal explant adjacent to a laminin-tenascin border. A GFP-FRNK–expressing neurite crossed into tenascin (arrow), whereas wild-type neurites, labeled by  -tubulin immunofluorescence (red), remained on laminin. (m) Effects of reduced FAK activity on substratum-dependent neurite turning. WT, wild type. n > 150 neurites from eight cultures for each condition. Scale bars: 7  m in a–c, g–h; 50 m in k–l. Data are mean  s.e.m. *
P < 0.05, **
P < 0.001.
|
| | | |  |
|
