Transferrin-containing vesicles move to mitochondria. (A) Confocal micrograph time series of a representative reticulocyte with labeled mitochondria (red) and holo-transferrin (green). Panels proceed from left to right with a 50 ms interval. Arrows in the leftmost panel of each row highlight some of the vesicles that appear to interact with mitochondria over the course of the videomicrograph. Cell diameter is approximately 8 μm. The corresponding videomicrograph is shown in Video S3. (B-D) TEM images of reticulocytes labeled with HRP-Tf. M, mitochondrion; arrows indicate HRP-Tf. Scale bar is 200 nm.