Figure 5. DHEA induces TrkA- and p75^NTR-mediated signaling.

(A) upper panel: HEK293^TrkA transfectants were exposed for 10 and 20 min to 100 nM of DHEA or 100 ng/ml of NGF, and cell lysates were immunoprecipitated with anti-tyrosine antibodies and analyzed by Western blotting, using specific antibodies against TrkA receptors. lower panel: Serum deprived naive or siRNA^TrkA transfected PC12 cells were incubated for 10 min with 100 nM of DHEA or 100 ng/ml of NGF and cell lysates were analyzed with Western blotting, using specific antibodies against the phosphorylated and total forms of TrkA receptor and of Shc, ERK1/2, and Akt kinases. (B) HEK293 cells were co-transfected with the plasmid cDNAs of p75^NTR and of each one of the effectors TRAF6, RIP2, or RhoGDI, tagged with the flag (TRAF6) or myc (RIP2, RhoGDI) epitopes. Transfectants were exposed for 30 min to 100 nM of DHEA or 100 ng/ml of NGF, and lysates were immunoprecipitated with antibodies against flag or myc, followed by immunoblotting with p75^NTR specific antibodies.