Fig. 1: Leading process in migrating neurons shares morphological and molecular features with axonal growth cone.
From: Identification of the growth cone as a probe and driver of neuronal migration in the injured brain
a, b Time-lapse images of Venus-CAAX-labeled axon and leading process (LP) of differentiating (a) and migrating (b) neuron, respectively. Blue and pink arrows indicate tip of axonal growth cone and LP growth cone-like structure, respectively. Arrowhead indicates transient collapsed state of LP growth cone-like structure. c Migration speed in LP elongation and pause phases. d, e Representative images of an axonal growth cone (d) and LP growth cone-like structures (e) stained with phalloidin (green) and immunolabeled with antibodies targeting tyrosinated-tubulin (magenta) and acetylated-tubulin (cyan). Arrows indicate F-actin and tyrosinated tubulin-positive signals. f, g Representative super-resolution images of axonal (f) and LP (g) growth cones with labelling of GFP (green) and of the axonal growth cone molecules Destrin, Liprin-α, PTPσ, and Syntaxin-7 (red and pseudocolors [numbers indicate 16-bit depth]). Dotted lines indicate the segmented growth cone area (GC). h Colocalization of PTPσ (red), Liprin-α (cyan), and F-actin (green) in the LP growth cone. i Representative super-resolution images of LP growth cones of control and Liprin-α-KD cells stained for GFP (green) and PTPσ (red). Arrows indicate PTPσ+ signals in the leading shaft. Quantification of PTPσ localization in the growth cone and leading shaft of control and Liprin-α-KD neurons is shown. j Experimental scheme for analysis of CSPG-PTPσ signaling. k–p Time-lapse images (k–n), growth cone area (o), and migration speed (p) of Venus-CAAX (green)- and DsRed (red; k–m, control; n, PTPσ-KD)-expressing migrating neurons cultured in Matrigel (magenta zone) with (l–n) or without k CS. Arrows indicate tips of growth cones (k–n). q Common morphological and molecular features of axonal and LP growth cones. Numbers indicate time in min (a, b, k–n) from the first imaging frame. Scale bars: a, b, f–h, 2 µm; d, e, i, k–n, 5 µm. *p < 0.05, ***p < 0.005. Error bars indicate mean ± SEM.
