Fig. 3.
The effects of cell differentiation on Rac1 transamidation. (A) A1A1v cells were incubated at 37°C for 4 days to induce differentiation. Compared to undifferentiated cells (left), differentiated cells (right) develop a neuron-like cell shape with long neurites. (B) Cells were treated with 3 μM DOI for 15 minutes, followed by immunoprecipitation and immunoblot analysis. Stimulation of 5-HT2A receptors by DOI increased the TGase-catalyzed transamidation of Rac1 in both undifferentiated and differentiated cells. (C) Quantitation of immunoblots for 3 separate experiments. Data shown are the mean IOD ± SEM and normalized to vehicle-treated control levels in undifferentiated cells. Two-way ANOVA indicates a significant main effect of DOI treatment (F(1,8)=49.48, p<0.01). However, there was no significant main effect of cell differentiation on TGase-modified Rac1 (F(1,8)=4.07, p=0.08). The interaction between DOI treatment and cell differentiation was also not significant for TGase-modified Rac1 (F(1,8)=0.34, p=0.58). Newman-Keuls Multiple Comparison Test indicates p<0.01* as compared to vehicle treatment in undifferentiated cells, p<0.01# as compared to vehicle treatment in differentiated cells. Scale bar, 105 μm.