Curvature-induced expulsion of actomyosin bundles during cytokinetic ring contraction
- University of Warwick, United Kingdom
- King's College London, United Kingdom
- Lawrence University, United States
Figures
Figure 1 with 1 supplement
Large actin bundles are expelled during actomyosin ring contraction.
(A) S. japonicus cells expressing LifeAct-GFP. (B) Spheroplasts expressing LifeAct-GFP. (C) Permeabilized spheroplasts (by 0.5% NP-40) stained with CF633-phalloidin. (D) Quantification of the widths …
Figure 1—figure supplement 1
Analysis of actin bundles during actomyosin ring contraction and disassembly in S. japonicus and S. pombe.
(A) Intact cells and spheroplasts of S. japonicus wild type and wild type expressing LifeAct-GFP or Rlc1p-GFP were permeabilized and stained with Rhodamine-conjugated phalloidin. Arrows indicate …
Figure 2 with 1 supplement
Quantitative analysis of actomyosin bundle expulsion.
(A) Top panel: localizations of tropomyosin Cdc8p and Rlc1p-GFP in permeabilized spheroplasts. Both proteins were detected by immunofluorescence microscopy. Bottom panel: spheroplasts expressing …
Figure 2—figure supplement 1
Analysis of actomyosin ring components during ring contraction and disassembly.
(A) S. pombe spheroplasts expressing Rlc1p-GFP shows expulsion of actomyosin bundles. (B) Quantification of the Rlc1p-GFP ring contraction rate (diameter and perimeter change over time) and ring …
Figure 3 with 1 supplement
Expulsion of actomyosin bundles during contraction of isolated rings.
(A) i, bundle expulsion mediated by cytosolic proteins; ii, newly polymerized actin filaments that are unable to incorporate into a highly curved actomyosin ring. (B) Time-lapse micrograph shows …
Figure 3—figure supplement 1
Contraction of the isolated Rlc1p-GFP ring in cell ghosts upon ATP treatment.
(A) Contraction of an isolated actomyosin ring in a cell ghost expressing Rlc1p-GFP treated with 0.5 mM ATP. No obvious Rlc1p-GFP bundle was visualized. The time is indicated at the top right corner …
Figure 4 with 1 supplement
Increased ring curvature promotes actomyosin bundle expulsion.
(A) Analysis of the curvature of sliding rings in spheroplasts expressing Rlc1p-GFP (n = 11 rings). The ring curvatures were color-coded, and mean curvatures of each stage of contraction are shown …
Figure 4—figure supplement 1
Curvature analysis of actin rings in cell ghosts and Rlc1p rings after compression of spheroplasts.
(A) Association of actin bundles with curved edges in isolated rings after 20 min ATP addition. Cell ghosts were stained with CF633-phalloidin, n = 220 bundles from 75 cell ghosts. Green arrows …
Videos
Video 1
Expulsion of F-actin bundles during ring contraction in a spheroplast expressing LifeAct-GFP.
Asterisks mark the elongation of an actin bundle. Left panel is presented in 'Fire' lookup table and its calibration bar. Spheroplasts are outlined by dotted lines. Time zero indicates the start of …
Video 2
Expelled filaments/bundles contain GFP-Rng2p, Cdc15p-GFP, and Rlc1p-GFP.
Asterisks indicate expelling bundles. Time zero indicates the start of the video.
Video 3
Ring contraction in intact S. japonicus cells expressing Rlc1p-GFP.
Asterisks indicate actomyosin bundles are expelled from the contracting rings. Time zero indicates the start of the video.
Video 4
Expulsion of actin bundles in 0.5 mM ATP-treated isolated rings in cell ghosts.
Asterisks indicate expelled actomyosin bundles during contraction. Time zero indicates the start of the video.
Video 5
Curvature-induced expulsion of actomyosin bundles in distorted rings.
Curvature of distorted rings is color-coded. Ring contraction is shown in three different angles of projections. Time zero indicates the start of the video.
Additional files
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Supplementary file 1
Table shows fission yeasts S. japonicus and S. pombe strains used in this study.
- https://doi.org/10.7554/eLife.21383.015
