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Fig. 2. F-actin foci colocalize with β1 integrin receptors and the PC proteins PXN and FAK in growth cones. (A-C) Confocal microscopy images of growth cones cultured on laminin and immunolabeled for β1 integrin (A), pY118-PXN (B) or pY397-FAK (C). (A′-C′) Phalloidin staining. (A′-C′) Merged images of immunolabeling (green) and F-actin staining (red). Note that β1 integrin targets to filopodia tips (solid arrowheads), as well as to F-actin foci (open arrowheads). Also note that pY118-PXN and pY397-FAK colocalize with some (open arrowheads), but not all, F-actin foci (solid arrowheads). (D) A minority of F-actin foci contain pY118-PXN. ***P<0.001, unpaired t-test, n=68. (E,F) Inverse contrast TIRF images of a live spinal neuron growth cone on laminin expressing both paxillin (PXN)-GFP (E) and mCh-UtrCH (F). (G) In a merged pseudo-colored image, PXN (green) colocalizes with some (open arrowheads), but not all F-actin foci (red, solid arrowheads). Scale bars: 5 µm (A,B,E-G). |
