FIGURE 7.

Sema3A-induced CRMP2 phosphorylation at Tyr³² and suppression of Sema3A-induced growth cone collapse by introduction of the nonphosphorylated mutant. A, COS-7 cells were transfected with PlexinA2, NRP1, Fyn, and CRMP2-Myc. After being stimulated with 3 nm Sema3A, the cell lysates were immunoblotted with anti-pCRMP (Y32) antibody and anti-Myc antibody. A typical immunoblot analysis is shown. B, chick E7 DRG neurons were infected with recombinant herpes simplex virus preparations directing the expression of CRMP2wt or the CRMP2Y32F mutant. Expression of CRMP2wt did not alter Sema3A-induced growth cone collapse, whereas expression of CRMP2Y32F suppressed the Sema3A response. Scale bar, 20 μm. C, rate of growth cone collapse of CRMP2wt- or CRMP2Y32F-expressing DRG neurons stimulated with Sema3A (0.5 nm). Data include mean values ± S.E. for n = 9–13. *, p < 0.01, significantly different from no virus control using analysis of variance.