FIGURE 8.

Phosphorylation of Ser-922 by PKC decreases dendrite arborization. A–D, representative tracings of cortical neuron dendritic arbors from cultures transfected at low efficiency with an empty vector (Control), A3-WT, A3-S/A, or A3-S/D plus GFP and treated for 3 days with vehicle only (DMSO), Gö6983, or PMA. E–G, Sholl analysis curves of all transfection conditions treated with vehicle (E, DMSO), Gö6983 (F, Gö), or PMA (G). H, area under the curve representation of data shown in E–G, compared with control or A3-WT-expressing neurons, neurons expressing A3-S/A exhibit increased dendrite complexity, whereas those expressing A3-S/D exhibit reduced dendrite complexity (E and H). PKC inhibition (Gö6983 treatment) did not further increase arborization in A3-S/A neurons, in contrast to all other conditions, where PKC inhibition elevates (control, A3-WT) or rescues (A3-S/D) arborization (F and H). Because PMA is a broad activator of PKC, which is known to inhibit dendrite arborization downstream of γ-Pcdhs, PMA treatment reduced arborization to similarly low levels in all neurons examined (G and H). Treatment of neurons expressing A3-S/D with PF-228 rescued arborization to control levels (H). Graphs show results from three separate cultures ± S.E., 20–60 neurons per condition. *, p < 0.05; **, p < 0.01; ***, p < 0.001. The bar in A is 100 μm. PF, PF-573,228.