Figure 10.

Sequential images of ER tubule elongation along actin bundles and the colocalization of elongated tubules along them. The S12 fraction was mixed with 2 mm ATP, 0.5 mm GTP, and 5 μg mL⁻¹ RP-F-actin. The numbers at top right in A to N indicate the time in seconds. O shows an image of RP-F-actin, and P shows the merged image of N and O. The green and magenta signals show the GFP-ER and RP-F-actin, respectively. Arrowheads indicate the tip of the ER tubule. Arrows 1 in C and 2 in M indicate the positions of actin bundles shown in O. From A to C, the ER tubule slid at 1.2 μm s⁻¹ along actin bundle 1, while it slid at 1.1 μm s⁻¹ from J to K, 2.8 μm s⁻¹ from K to L, and 1.9 μm s⁻¹ from L to M along actin bundle 2. Bar = 5 μm.