Fig. 5. The conserved tyrosine residues in Dok-4 are important for GDNF-dependent neurite outgrowth in TGW cells. (A) TGW cells and TGW cells stably expressing each mutant were serum-starved and stimulated with GDNF (50 ng/ml) for 48 hours. (B) Mean of the longest neurite was determined for each culture from measurements of 100 neurons for three different experiments. Each data point represents the mean ± s.e.m.