Figure 2.

Deletion of CSPG receptor PTPσ facilitates pTRKB and delays closure of the critical period in the visual cortex of adult mice. A, PTPσ can be immunoprecipitated with anti-TRKB antibody in samples from a TRKB-expressing, but not from a TRKA-expressing, cell line. B, Interaction of TRKB and PTPσ is reduced in embryonic cortical cultures from PTPσ^+/− mice when compared with those from WT mice. C, pTRKB is increased in cortical cultures from PTPσ^+/− and PTPσ^−/− mice. D, Adult PTPσ^+/− mice have increased pTRKB and (E) a slight decrease in total TRKB levels in the visual cortex. F, Critical period-like plasticity is present in the visual cortex of two-month-old PTPσ^+/− mice (red circles) but not in WT littermates (black squares), as measured by optical imaging of the intrinsic signal before (IOS1) and after 3.5 d of MD (IOS2). ODI: ocular dominance index. Columns and bars represent mean ± SEM, respectively, and scattered points represent individual values. Data were analyzed by two-way (F) or one-way ANOVA (C) followed by Bonferroni's or Tukey's post hoc, respectively; unpaired t test (B) or Mann–Whitney test (D, E); *p < 0.05, **p < 0.005, ***p < 0.0005.