 | Figure 3
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 3. FAK promotes point contact tyrosine phosphorylation and growth cone motility.
(a–c) Growth cone on laminin immunolabeled with primary antibodies to phosphoY397-FAK (anti–pY397-FAK) and PY99, and stained with fluorescent phalloidin to label F-actin. (d) Merged image. Note colocalization between pY397-FAK and PY99 within point contacts (arrowheads) but not at filopodial tips (arrows). (e–h) Growth cones on laminin (e,f) and tenascin (g,h) labeled for pY397-FAK and merged with F-actin staining. (i) Quantification of pY397-FAK immunofluorescence intensity within growth cones on laminin and tenascin, normalized to average values on laminin. n > 30 growth cones for each condition. (j) Immunoblot for FAK from whole embryo lysates of control embryos and embryos injected with xFAK morpholino. Blot was reprobed for vinculin (vinc) to control for protein loading. (k) Reduced FAK activity decreased PY99 and pY118-paxillin immunofluorescence (IF) at the growth cone periphery. n > 30 growth cones in three cultures for each condition. (l,m) Effects of FAK inhibition on neurite growth rate and filopodial lifetime on laminin. n > 20 growth cones and 100 filopodia for each condition. (n–q) Control (n,o) and FRNK-expressing (p,q) growth cones on laminin labeled for pY118-paxillin and F-actin. Note punctate pY118-paxillin immunofluorescence in control growth cone lamellipodia (arrowheads). Scale bars: 5  m in a–d,n–q; 7 m in e–h. Data are mean  s.e.m. *
P < 0.05, **
P < 0.001. LN, laminin; TN, tenascin.
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