Figure 3. TrkB‐FL preserved by TFL₄₅₇ action maintains Y816 phosphorylation and PLCγ‐dependent pathways required for neuroprotection.

• A
  TrkB‐FL main signaling cascades with indication of anchoring residues, tested drugs, and their targets.
• B
  Effect of TFL₄₅₇ on Y515 and Y816 phosphorylation. Cultures preincubated with TMyc or TFL₄₅₇ (25 μM, 30 min) were treated with NMDA (0–6 h) and analyzed with panTrkB or phosphospecific antibodies.
• C
  Quantitation of pY515 and pY816. Mean ± SEM of normalized pY515 (n = 7) or pY816 (n = 4) levels obtained after NMDA treatment (2 h) is represented relative to those found in cells with the same peptide but no NMDA. Statistical analysis was performed by unpaired Student's t‐test (*P = 0.046; n.s. = non‐significant).
• D
  Analysis by immunoprecipitation of TFL₄₅₇ effect on pY816 levels. Cultures preincubated and treated as before with NMDA (2 h) were immunoprecipitated with antibodies specific for phosphorylated tyrosine (pY). pY816 was analyzed by WB in immunoprecipitates.
• E
  TFL₄₅₇ effects on neuronal viability after inhibition of TrkB‐FL signaling. Cultures were preincubated (30 min) with inhibitors specific for PI3K (Wortmannin, 100 nM), MAPK/ERK (UO126, 300 nM), or PLCγ (U‐73122, 5 μM) before incubation with TMyc or TFL₄₅₇ (25 μM, 30 min). Viability was established 4 h after NMDA treatment. Means ± SEM relative to untreated cultures are represented, and data were analyzed by ANOVA test followed by post hoc Tukey's HSD test (***P = 0.0001, **P = 0.009, *P = 0.02, n.s. = non‐significant, respectively, for TMyc vs. TFL₄₅₇ in untreated or Wortmannin, UO126, or U‐73122‐treated cells; **P = 0.008 for untreated vs. U‐73122‐treated cells preincubated with TFL₄₅₇; n = 5).

Source data are available online for this figure.