Figure 4
Distribution and requirement of phospho-FAK (pFAK) at presynapses of neuromuscular junctions (NMJs). (A-D) Active Fak56 (pFAK in magenta) recognized by anti-FAK [pY397] antibodies localized at presynapses of NMJ 12/13 (A) and NMJ 4 (B) in wild-type larvae, and was absent in Fak56N 30/K 24(C), and reduced in βν1/1 (D), with co-stained horseradish peroxidase (HRP) in green. White arrows and arrowheads indicate Ib and Is boutons, respectively. Images in (A-D) come from a single section of the Z-stack confocal scanning. Note punctate distribution in muscles and strong expression in axonal trunks (yellow arrowhead in B1) surrounded by HRP membrane staining. The inset image in B1 is the inclusion of pFAK inside the incoming axon from a Z-stack section crossing the middle of the axon. (A2-D2) are diphospho-ERK (dpERK) images in white. (E-F) Images of NMJ 6/7 are shown as for Figure 1. Neuronal overexpression of LacZ control (E) or Fak56Y 430F(F) by elav-GAL4 displays a NMJ overgrowth phenotype. (G) Quantification of NMJ 6/7 phenotypes for elav>LacZ, elav>Fak56 and elav>Fak56Y430F. Note that elav>Fak56 shows slight reduction in bouton number and NMJ length when compared to elav>LacZ control (E) but these reductions were not statistically significant (p = 0.413 for bouton number and p = 0.125 for branch length in Student's t-test). Asterisks indicate significant difference by Student's t test (p < 0.05) and error bars represent the standard error of the mean (SEM).