The midbody remnant moves along the apical surface from a peripheral to a central position to encounter the centrosome. (A and B) XY confocal stack of cells coexpressing GFP-PRC1 and cherry-tubulin (A) and GFP-tubulin and dsRed-centrin (B) during movement of the midbody remnant. In A, the green and red arrowheads point to the midbody remnant pools of PRC1 and tubulin, respectively. In B, the green and red arrowheads point to the remnant and the centrioles, respectively. (C) 3D reconstruction of cells expressing GFP-tubulin during remnant movement (top). The images were pseudocolored based on height, using the color scale on the left, to highlight that the remnant moved to the center of the apical surface as the cell gained height. The green arrowhead points to the midbody remnant. The differential interference contrast (DIC) images show that the cell occupied 25% less area at the end (bottom). Bars, 5 µm. (D) EM micrograph of a cell with the remnant in the vicinity of the centrosome at the center of the apical surface and enlargements of different sections. The images are orthogonal serial sections from the same cell. Asterisks indicate cell junctions, the black arrowhead points to the remnant, and the arrow indicates the centrosome. The sections were numbered S1 onwards from the back to the front. Note that it appears that the remnant is connected to the rest of the cell by a thin tether, indicated by an empty arrowhead (see S2′, which is an enlargement of the boxed region of S2). Bars: (panoramic view) 4 µm; (enlargements) 500 nm. (E) 3D reconstruction of the central remnant (red), the tether (dark red), and adjacent apical membrane (gray) obtained by manual tracing and stacking of their contours after alignment of the serial EM sections of Fig. S3 B. The arrowhead indicates the tether.