Fig. 4.

PDNF in the cytosol of Schwann cells activates Akt. (A) Lysates of Schwann cells transfected with empty vector (Sc-Red) or with a plasmid encoding PDNF (Sc-PDNF) were analyzed by Western blotting with antibodies against PDNF, pAkt (Ser⁴⁷³), pAkt (Thr³⁰⁸), and Akt. The lower graph shows the ratio of pAkt to Akt in the lysates of Sc-Red and Sc-PDNF cells determined by scanning densitometry of the blot. (B) Specific trans-sialidase activity of infected and transfected Schwann cells. Specific enzyme activity in lysates of Schwann cells infected with T. cruzi (Sc-Inf) and in lysates (L) and culture supernatants (S) of Schwann cells transfected with plasmid encoding PDNF (Sc-PDNF) or with empty vector (Sc-Red). (C) Akt phosphorylates PDNF in transfected cells. Schwann cells transfected with empty vector (Sc-Red) or with a plasmid encoding PDNF (Sc-PDNF) were treated with the Akt inhibitor Akti VIII for 24 hours before harvesting. Cell lysates were immunoprecipitated with the PDNF-specific antibody TCN-2 and samples were then incubated with antibodies against Akt-phosphorylated substrates (αP-Akt sbstr). All the experiments were repeated at least three times with similar results.