Figure 4.

p600 is required for neurite extension. A, Colocalization of p600 with ER markers IP3R and Bip in phalloidin-positive growth cones. B, Altered neuronal processes associated with reduced staining of Bip in primary neurons cotransfected with GFP/p600 RNAi no. 1 or RNAi no. 2, 24 h after transfection when compared with adjacent nontransfected neurons (white arrowhead) or neurons cotransfected with GFP/control RNAi. C, Total collapse of neuronal processes in individual primary neurons cotransfected with GFP/p600 RNAi no. 1 or RNAi no. 2 (48 h) as evidenced by the lack of GFP and tubulin staining (black/white and blue in the fourth panel). All pictures were taken with a confocal microscope. Scale bars: A, 5 μm; B, C, 10 μm.