CGNs were treated for 30 min with netrin-1, GDNF, L1-Fc, or BDNF in the absence and presence of 5 µM PP2. The ratio of pY416SFK to Fyn kinase was normalized to control values in each experiment. Shown is the mean ± SEM normalized ratio following the indicated treatments. Representative immunoblots show phosphorylated Y416SFK, detected with pY416SFK antibody (top panels), and total Fyn kinase, detected with Fyn kinase antibody (bottom panels). * p < 0.05; ** p < 0.01; compared to control; # p < 0.05 between indicated groups (n = 3–9 independent experiments).