Involvement of RA-RhoGAP in the neurite extension downstream of DGKβ. A, effect of RA-RhoGAP knockdown on the neurite outgrowth in the DGKβ-overexpressing NG108 cells. NG108 cells were co-transfected with GFP as a morphological marker along with both scramble RNA (Scramble) and myc-DGKβ or both RA-RhoGAP siRNA and myc-DGKβ, cultured in DMEM supplemented with 10% FBS for 48 h, and allowed to extend neurites. The cells expressing the RA-RhoGAP siRNA or the scramble RNA were identified by the expression of GFP (green). The expression of myc-DGKβ was examined by immunostaining with the anti-Myc pAb (red). It is noted that the RA-RhoGAP siRNA is the same one as used in the previous study (15). Bars, 50 μm. B, quantitative analysis of the neurite outgrowth of the transfected NG108 cells. Panel a, quantitative analysis of the number of neurites per transfected cell as in Fig. 3C, panel a. Panel b, quantitative analysis of the length of neurites per transfected cell as in Fig. 3C, panel b. Panel c, quantitative analysis of the number of branch tips per transfected cell as in Fig. 3C, panel c.