Figure 4.

ARL2 and BART cosediment with the inner matrix marker mtHSP70 after density gradient centrifugation. Heavy mitochondria were isolated from sf295 cells by differential centrifugation, applied beneath a continuous 10–30% Optiprep (Iodixanol) gradient, and centrifuged at 52,000 × g for 90 min, as described under MATERIALS AND METHODS. The gradient was then fractionated (bottom to top) and equal-volume samples from individual fractions were analyzed by immunoblot with the indicated antibodies. Similar results were obtained multiple times and by using combined light and heavy mitochondria from sf295 cells or rat brains.