Fig. 2. Increases in PIP3 by activation of PI3K or inactivation of PTEN antagonises Sema3A-induced growth cone collapse. (A) Chick DRG explants were cultured overnight in the presence of NGF. Prior to application of Sema3A-Fc at 1 µg/ml, the cultures were incubated with the PI3K-activating 740Y-P peptide at 40 µg/ml for 30 minutes, with the 740Y-P peptide and LY294002 (10 µM), or with the Y-P-peptide 1309 (at 40 µg/ml). (B) GFP, GFP-PTEN or phosphatase-deficient GFP-PTEN C124S were nucleofected into chick DRG neurons, cultured for 24 hours and stimulated with Sema3A as before. Each data point is the mean ± s.e.m. of at least three independent experiments; ^*P<0.05.