(A) BDNF levels measured by ELISA in the forebrains of P30 Mecp2^–/y mice (gray bar) compared with WT animals (black bar) (n = 10, Student’s t test, P = 0.015). (B) BDNF levels measured by ELISA in the forebrains of 10-week-old Mecp2^–/+ mice (gray bar) compared with WT animals (black bar) (n = 10, Student’s t test, P = 0.023). (C) Tyrosine-phosphorylated proteins were immunoprecipitated from saline- and CPT157633-treated WT or Mecp2^–/+ mice, and immunoprecipitates were blotted for TRKB (upper panel). TRKB levels in each sample were measured by immunoblotting the lysate with anti-TRKB antibody (lower panel). (D) Brain lysates obtained from CPT157633-treated WT female mice were incubated with WT PTP1B or substrate-trapping mutant PTP1B-D181A, in the presence or absence of pervanadate. PTP1B immunoprecipitates were subjected to SDS-PAGE and immunoblotted with an antibody recognizing TRKB (upper panel) and PTP1B (lower panel). (E) WT and mutant forms of FLAG-TRKB were expressed in SH-SY5Y cells. Unstimulated and BDNF-stimulated cells were lysed and subjected to immunoprecipitation using anti-FLAG antibody. The immunoprecipitated samples were resolved on SDS gels and immunoblotted using the anti-phosphotyrosine antibody 4G10. (F) BDNF-stimulated lysates from SH-SY5Y cells expressing WT and mutant forms of TRKB were incubated with the substrate-trapping mutant form of PTP1B, and immunocomplexes were resolved on SDS gels and immunoblotted using anti-FLAG antibody to monitor the expression of TRKB. (G) Representative blot showing that CPT157633 treatment resulted in enhanced phosphorylation of Y705/Y706-TRKB on Mecp2^–/+ brain. (H) Representative blot showing the effects of CPT157633 treatment on tyrosine phosphorylation of the TRKA receptor in Mecp2^–/+ brain. (I) Representative blot showing the effects of CPT157633 treatment on tyrosine phosphorylation of the TRKC receptor in Mecp2^–/+ brain. All blots (C–I) are representative of experiments performed 3 times.