Figure 7.

Association between Golgi-derived tubules and ER exit sites. Images were captured at 37°C at various times after treatment with 5 μg/ml BFA. The cells transiently coexpress GalT-CFP and p58-YFP (A; n = 7, imaging initiated at 01:15) or GalT-CFP and Sec13-YFP (B; n = 7, imaging initiated at 04:28). Tubules that contain GalT-CFP are associated with p58-YFP-positive puncta very rapidly after the tubulation event (∼6 min) with p58-YFP-containing puncta remaining attached throughout the period of tubulation (∼10 min, white arrowheads in A; and Video 5, A and B). There are also p58-YFP puncta that seem not to connect with GalT-CFP tubules (A, 06:45 outlined arrowheads). The tips or tubule branching points of all GalT-CFP-positive tubules associate with the Sec13-YFP-positive ER exit sites (white arrowheads in B; and Video 6, A and B). Bars, 10 μm.