FIGURE 6.

Signaling through Tyr⁶⁸⁷ is required for RET-mediated neurite outgrowth in sympathetic neurons. A, representative micrographs of dsRed-expressing SCG neurons 30 h after microporation with the indicated constructs maintained in the presence of 1 ng/ml NGF. Examples from wells maintained in only 100 and 1 ng/ml NGF are also shown. B, camera lucida drawings depicting the longest neurites of transfected SCG neurons in 10 different fields superimposed onto each other. C, neurite outgrowth in SCG neurons transfected with wild type or Y687F mutant MEN2A RET constructs. Neurite outgrowth was measured as the length of the longest neurite in each transfected neuron and normalized to the average values obtained with 100 ng/ml NGF. Results are expressed as the average ± S.D. of three independent experiments each performed in triplicate. *, p < 0.05 versus WT (corresponding solid bars).