Figure 9.
A, B. Total Internal Reflection Fluorescence (TIRF) microscopy images of paxillin-GFP and mCherry dual-Src homology 2 domain (mCh-dSH2) fluorescent images of a growth cone on PDL-laminin. Note that paxillin and phosphotyrosine (PY), as revealed with mChdSH2, colocalize at adhesion sites (arrowheads in A, B), whereas the tip of a growing filopodium has PY, without paxillin (arrow in B). C. Merged image of the growth cone in (A, B) shows co-localization at several peripheral adhesions. Note that mCh-dSH2 puncta within the central domain are mobile vesicles. D. Single line kymograph constructed from region between the arrowheads in C. Note a stable adhesion (arrow) that disassembles after a new protrusion extends forward, followed by the formation of a second adhesion (arrowhead), which stabilizes the receding protrusion. Scale bar, 10 μm in all images and as indicated in kymographs. With permission from Santiago-Medina et al. (2012) Dev. Neurobiol. 72, 585-599.