Maturation of the MR is accompanied by both removal and retention of Anillin. (A) Time-lapse sequence of a cell expressing Anillin-GFP and mCh-tubulin (40× objective). Arrowheads mark the mature MR before and after abscission MR release. (B–D) Time-lapse sequence of cells expressing Anillin-GFP and mCh-tubulin (not depicted) acquired with 40× objective, showing extrusion and shedding (B and C) and internalization (D). Boxed regions in B and D are shown magnified at the bottom; dashed lines in C mark the cell boundary; arrowheads mark shed material. (E) Relative Anillin-GFP fluorescence (sum intensity) at nascent MRs measured from the end of furrowing (means ± SD; n = 20). (F) FRAP experiments of nascent and mature MRs, showing images acquired immediately before (prebleach), after (bleach), and 4 min after high-intensity illumination of the outlined region of interest (63× objective and 2 × 2 camera binning). (G) The percent recovery of GFP fluorescence within 4 min of bleaching is shown for MRs of different ages (n = 9–17 each, means ± SD). P-value is for an unpaired t test. Times are hours, minutes, and seconds from the end of furrowing. Bars, 5 µm. See also Videos 1 and 2.