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F-actin dismantling through a redox-driven synergy between Mical and cofilin

Nature Cell Biology volume 18, pages 876–885 (2016)Cite this article

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Abstract

Numerous cellular functions depend on actin filament (F-actin) disassembly. The best-characterized disassembly proteins, the ADF (actin-depolymerizing factor)/cofilins (encoded by the twinstar gene in Drosophila), sever filaments and recycle monomers to promote actin assembly. Cofilin is also a relatively weak actin disassembler, posing questions about mechanisms of cellular F-actin destabilization. Here we uncover a key link to targeted F-actin disassembly by finding that F-actin is efficiently dismantled through a post-translational-mediated synergism between cofilin and the actin-oxidizing enzyme Mical. We find that Mical-mediated oxidation of actin improves cofilin binding to filaments, where their combined effect dramatically accelerates F-actin disassembly compared with either effector alone. This synergism is also necessary and sufficient for F-actin disassembly in vivo, magnifying the effects of both Mical and cofilin on cellular remodelling, axon guidance and Semaphorin–Plexin repulsion. Mical and cofilin, therefore, form a redox-dependent synergistic pair that promotes F-actin instability by rapidly dismantling F-actin and generating post-translationally modified actin that has altered assembly properties.

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Figure 1: Mical/F-actin dynamics are modulated by cofilin.
Figure 2: Cofilin slows F-actin oxidation by Mical but accelerates filament disassembly.
Figure 3: Mical-mediated oxidation of actin alters polymerization and weakens the mechanical properties of filaments.
Figure 4: Mical oxidation of F-actin improves cofilin binding and results in accelerated filament severing.
Figure 5: Cofilin enhances Mical-mediated F-actin alterations in vivo.
Figure 6: Cofilin enhances Sema–Plexin–Mical repulsive axon guidance.

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Acknowledgements

We thank H. Kramer, M. Quinlan and M. Rosen for comments, G. Marriott (UC Berkeley, USA) for the gift of kabiramide C, and J. Merriam (UCLA, USA), the Bloomington Stock Center, the Kyoto Drosophila Genetic Resource Center, the Vienna Drosophila Resource Center, and FlyTrap for flies. This work was supported by US Public Health Service grants to E.R. (GM077190) and J.R.T. (NS073968) and a Welch Foundation grant (I-1749) to J.R.T.

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Author notes

  1. Elena E. Grintsevich and Hunkar Gizem Yesilyurt: These authors contributed equally to this work.

Authors and Affiliations

  1. Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, USA

    Elena E. Grintsevich & Emil Reisler

  2. Departments of Neuroscience and Pharmacology and Neuroscience Graduate Program, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA

    Hunkar Gizem Yesilyurt, Shannon K. Rich, Ruei-Jiun Hung & Jonathan R. Terman

  3. Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California 90095, USA

    Emil Reisler

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Contributions

E.E.G. characterized Mical/cofilin NADPH consumption, collected and analysed all TIRF microscopy data, developed and carried out subtilisin proteolysis assays, and performed and analysed experiments with Q41C and ANP-modified actin; H.G.Y. performed and analysed NADPH consumption assays, bulk actin disassembly, co-sedimentation and immunochemistry experiments; H.G.Y., S.K.R. and J.R.T. collected and analysed the in vivo data; R.-J.H. and J.R.T. developed the strategy and characterization of the MetO44 and wild-type Met44 antibodies; R.-J.H., E.E.G. and H.G.Y. characterized Mical-oxidized actin; all authors designed experiments; E.E.G., H.G.Y., J.R.T. and E.R. wrote the paper; S.K.R. and R.-J.H. edited the paper; J.R.T. and E.R. oversaw all aspects of the project in their respective groups.

Corresponding authors

Correspondence to Jonathan R. Terman or Emil Reisler.

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Integrated supplementary information

Supplementary Figure 1 Further characterization of the interaction of Mical and cofilin in modulating F-actin disassembly and the quantification of Mical-oxidized actin.

(a) Cofilin alone does not modify Mical’s enzymatic activity, unlike Mical’s substrate F-actin (Fig. 1b, c; refs 1), or cofilin in the presence of F-actin (Fig. 1b, c). Mean ± s.e.m. n = 3 independent experiments per condition. [Mical] = 600 nM, [NADPH] = 200 μM. (b–e) Pyrene actin assays with different combinations of cofilin, Mical, NADPH, and cofilin buffer. Compare with Fig. 1e–i. Note, that the enhanced effect of cofilin on Mical-mediated actin filaments disassembly is not observed in the absence of Mical’s coenzyme NADPH. [Actin] = 2.5 μM; [Cofilin] = 0.25 μM; [Mical] = 10 nM; [NADPH] = 100 μM. n = 3 independent experiments per condition. (f) Limited proteolysis assay with subtilisin allows quantification of Mical-oxidized actin. This assay is based on the unique feature of Mical-oxidized actin (ox-actin)- its resistance to limited proteolysis by subtilisin that normally occurs between residues 47 and 48 on actin2. F-actin and F-actin complexes with its binding partner (such as cofilin) are oxidized by Mical in the presence of NADPH. At the selected time points, oxidation is stopped with a large excess of NADP + (product of the reaction) and the actin depolymerizing reagent Kabiramide C (KabC)3. The resulting samples are subjected to limited proteolysis with subtilisin. Subtilisin A (type VIII, Bacillus licheniformis, 11.8–12 units mg−1 solid) was purchased from Sigma (P5380). The amount of ox-actin in the resulting samples was determined by SDS-PAGE and densitometry analysis. See also Supplementary Fig. 2a–c.

Supplementary Figure 2 Further characterization of Mical-oxidized actin using a limited proteolysis assay with subtilisin and an antibody directed against the Met-44 residue of actin.

(a–c) Development of limited proteolysis-based assay for quantification of Mical-oxidized actin (see also Supplementary Fig. 1f). Assay was developed based on the following observations: (1) Mical oxidizes actin at residue 47 (D-loop)1; (2) subtilisin cleaves actin between residues 47 and 48 (ref. 2); (3) under our experimental conditions Mical oxidized actin (ox-actin) cannot be cleaved by subtilisin at position 47/48, as opposed to unmodified actin, G-actin-cofilin, and G-actin-KabC complex; (4) Mical oxidation of actin can be inhibited by a large excess of the product of the reaction (NADP+); and (5) a combination of NADP + and the F-actin depolymerizing agent KabC3 stops Mical oxidation of actin. (a) The small actin sequestering molecule KabC does not affect limited digestion (proteolysis) of actin by subtilisin compared to G-actin alone; ox-actin—Mical-oxidized G-actin; cofilin—human cofilin-1; Digestion time (in minutes) is indicated in the panel. Conditions: 2 mM Tris, pH 8, 0.2 mM CaCl2, 0.2 mM ATP, 1 mM DTT; 1:1,000 subtilisin:actin w/w ratio. (b) Mical oxidation of actin/NADPH consumption can be stopped by an excess of NADP + (product of the reaction) in combination with KabC. NADPH consumption was followed by a decrease of its fluorescence at 460 nm (excitation wavelength was 340 nm). [F-actin] = 3.5 μM, [NADP+] = 1.5 mM, [KabC] = 3.5 μM, buffer: 20 mM imidazole, pH 6.8, 50 mM KCl, 2 mM MgCl2, 0.2 mM EGTA, 0.2 mM ATP, 1 mM DTT. (c) G-actin-cofilin complexes have the same subtilisin digestion pattern as uncomplexed G-actin; cofilin—human cofilin-1. [F-actin] = 3.5 μM, [cofilin] = 3.5 μM, [NADP+] = 1.5 mM, [KabC] = 3.5 μM, 1:200 subtilisin:actin w/w ratio. Conditions are the same as in (b). (d–e) Cofilin suppresses the Mical-mediated oxidation of actin, as observed using an antibody directed against the Met-44 residue of actin. (d) Characterization of an antibody that specifically recognizes the Met-44 residue of actin. Mical oxidizes actin on its Met-44 and Met-47 residues, but the oxidation of the Met-44 is instrumental for inducing F-actin disassembly1. This Met-44 residue of actin is conserved in all actins from yeast to humans (as are almost all of the surrounding residues)1. While attempting to generate antibodies to Mical-oxidized actin (using a peptide of actin residues 38–51), we identified anti-sera that preferentially recognized untreated actin from Mical-treated actin. In particular, note that the antibody (actinMet-44 antibody) preferentially recognizes untreated (Mical only) versus treated (Mical/NADPH) actin (d1, upper panel). This antibody specifically recognizes the Met-44 residue of actin since it does not recognize actin when the Met-44 residue is substituted with Leucine (M44L actin; d2), but does recognize actin when the Met-47 residue is substituted with Leucine (M47L actin; d2). Moreover, Mical-treated actin is recognized by the actinMet-44 antibody following treatment with SelR (d3), the reductase that reverses Mical-mediated oxidation of actin4. Note that similar amounts of Mical (d1, lower panel) and actin (d1–d3, lower panels) are present in all experiments. For western blotting, 2.3 μM of Drosophila actin (actin 5C) was polymerized with either 600 nM Mical alone (untreated [Mical only] actin) or 600 nM of Mical and 100 μM of NADPH (treated [Mical/NADPH] actin) for 1 h at room temperature. Then, Mical-treated actin was also treated with 2.4 μM of SelR (that we had previously generated4) in a buffer containing 20 mM DTT and 10 mM MgCl2 for 1 h at 37 °C. All samples were mixed with SDS-PAGE loading buffer, boiled for 5 min, and loaded onto a 12% SDS-PAGE. After transferring the proteins to a PVDF membrane, this membrane was blocked with 5% non-fat milk in PBST buffer for 1 h. This membrane was then incubated with either a pan actin antibody (C4; Millipore) or actinMet-44 antiserum for 1 h at room temperature, and followed with standard Western blotting procedures. Other mutant actin proteins that we had previously generated1 were also employed in our experiments, including both the Mical-resistant M44L and M44LM47L actins and the M47L actin. (e) Cofilin suppresses the Mical-mediated oxidation of actin, as observed using this actinMet-44 antibody (note the increased presence of actin that is recognized by this antibody in the presence of cofilin). [Actin] = 1.15 μM; [Cofilin] = 1.15 μM; [Mical] = 50 nM; [NADPH] = 100 μM. (f) Examples of the gels used to determine the Cc of purified Mical-oxidized actin (ox-actin) are shown in Fig. 3e (pH 8.0, quantified in Fig. 3e, blue circles). Total concentrations of ox-actin are indicated for each sample. S—Supernatant, P—Pellet. The determined Cc was ≥1 μM, which is consistent with the data shown in Fig. 3a–e. Thus, below its Cc values Mical-oxidized actin will not form filaments under polymerizing conditions. See also Supplementary Fig. 7 for uncropped gels of (d–f) and Supplementary Table 1 for source data for (f).

Supplementary Figure 3 Mical oxidation of actin filaments accelerates their severing by yeast and human cofilins.

(a) Severing of actin filaments in the presence of Mical/NADPH. Average of 3 independent trials is shown (analyzing 10–13 filaments each, n = 3 movies). Filaments were oxidized on-slide by addition of Mical (55 nM) and NADPH (100 μM) into the flow chamber. Filaments were allowed to oxidize for 1 min then movies were recorded. Note, that the oxidation-induced severing of F-actin by Mical can be followed for minutes (see also ref. 1) as opposed to its almost instant disassembly when combined with cofilin (compare to Fig. 4a). (b–d) Severing of unmodified F-actin (b) or its copolymer (11%) with Mical-oxidized actin (c) with yeast cofilin. Scale bar = 5 μm. (d) Time dependant change in the average length of skeletal F-actin and 11% Mical-oxidized actin copolymers in the presence of yeast cofilin. A dramatic acceleration of severing by cofilin was observed with 11% Mical-oxidized actin copolymer (c, d). This confirms that accelerated cofilin severing of 11% Mical-oxidized copolymer is not isoform specific (see Fig. 4b, c for comparison). Conditions: [Actin] = 1 μM (10% Cy3-maleimide labelled), [cofilin] = 3.3 nM, pH 6.8. (e) Determining the rates of human cofilin-1 severing of unmodified F-actin and its copolymer with Mical ox-actin from the TIRF data (related to the Fig. 4c). The plots are showing averages of 3 independent repeats for each condition. Red solid lines correspond to the linear fits used to determine maximum cofilin severing rates in Fig. 4c. Note, that in the case of the copolymers with Mical-oxidized actin, cofilin severing efficiency decreases over time (open circles). This effect is due to substantial shortening of actin filaments upon their extensive severing by cofilin within the observation time. Cofilin severs long filaments more efficiently than short filaments5. Since under our conditions such shortening is insignificant in the control sample (unoxidized actin), the dependence of the number of severing events per μm versus time is linear. To determine the maximum severing rates, linear parts of the traces were fitted individually for each repeat and the slopes were averaged (results are shown in Fig. 4c). n = 3 independent experiments per condition. Conditions: [Actin] = 1 μM (10% Cy3 labelled), [Cofilin] = 100 nM, pH 6.8.

Supplementary Figure 4 Indication of the enhanced cofilin severing and binding to actin filaments containing oxidized actin.

This figure presents analysis of the data from Supplementary Videos 5 and 6 . [Actin] = 0.6 μM, [yeast cofilin] = 38.5 nM, pH 6.8. One time point image (at 100 s) from the corresponding movie is shown next to each graph (Scale bar = 10 μm). After background subtraction (Rolling Ball Radius algorithm, 10 pxl), total fluorescence intensity per frame was determined in both channels (actin-Alexa488 (green) and cofilinCy5 (red)) and plotted versus time. The increase in fluorescence intensity is due to an increase in actin polymer mass (Alexa488 channel) and the mass of cofilin bound to these polymers (Cy5 channel). Note, that in both (a) and (b) the fluorescence intensity corresponding to actin and cofilin increases non-linearly within the observation time. This effect is due to the formation of new barbed ends as a result of cofilin severing activity. This tendency is more pronounced in the case of Mical-oxidized actin (ox-actin) copolymers (note the differences in the y axis scale between (a) and (b)). We determined the rates of fluorescence intensity change in both channels for unmodified actin and its copolymer with Mical ox-actin (11%). Changes in fluorescence intensity per second (which can be approximated by linear fits within chosen windows of time) are shown for two time intervals (0–90 s and 130–225 s) for each channel (solid black lines). Numbers shown next to each fit correspond to their slopes. Due to undersaturating concentrations of cofilin (38.5 nM), total actin fluorescence per frame increases faster than that of cofilin. Note, that in the control population (unmodified F-actin) actin-Alexa488 fluorescence increases ∼3–4 fold faster ([1.5 × 103/0.5 × 103] = 3 or [2.5 × 103/0.7 × 103] = 3.6) than that of cofilinCy5 ((a), Supplementary Video 5). However, in the copolymer sample, fluorescence of actin-Alexa488 increases only ∼2 fold faster ([4.0 × 103/2.0 × 103] = 2 or[9.6 × 103/4.6 × 103] = 2.1) than that of cofilinCy5 ((b), Supplementary Video 6). Thus, this decreased difference between cofilin and actin fluorescence in the Mical ox-actin copolymer sample is consistent with the presence of more cofilin associated with Mical-oxidized F-actin than with unmodified F-actin. This prompted our investigation of cofilin binding to the Mical-oxidized cross-linked F-actin (see Fig. 4d, e and Supplementary Fig. 5).

Supplementary Figure 5 Further characterization of cofilin binding to Mical-oxidized actin.

(a–d) Enhanced cofilin binding to cross-linked Q41C F-actin after its oxidation by Mical (see also Fig. 4d, e). (a) Positions of the cross-linked residues (41 (red) and C374 (blue)) in F-actin (PDB: 3J8A)6. Adjacent longitudinal protomers within the same actin strand are shown in grey. Actin third protomer from the opposite strand (lateral self-interacting interface) is shown in dark green. In the Q41C yeast actin mutant, residue 41 was mutated to cysteine which allows for disulfide cross-linking of this residue to native cysteine 374 on another protomer. (b) Representative SDS-PAGE gel under non-reducing (Coomassie stained) conditions demonstrates that Q41C actin is fully cross-linked by Cu2+ under our experimental conditions. Monomeric actin (left lane) is depleted upon CuSO4 addition (right lane) due to the formation of higher order actin species. (c) Cross-linked (XL) Q41C-F-actin can be fully oxidized by Mical. Efficiency of Q41C-XL oxidation by Mical was assessed by limited proteolysis with subtilisin. To this end, Q41C F-actin cross-linking was reversed with DTT after the indicated oxidation time (to allow it to appear as monomeric actin on the gel). Based on limited proteolysis with subtilisin, the increase in intensity of the uncleaved actin band over time reports on the progress of actin oxidation by Mical (ox-actin). Q41C-XL F-actin can be efficiently oxidized by Mical in the presence of NADPH (close to completion in 15 min). For cosedimentation assays with cofilin (Fig. 4d, e), Mical oxidation of Q41C-XL F-actin was carried out for 1 h at room temperature to ensure full oxidation. (d) Yeast cofilin binds tighter to the Mical-oxidized cross-linked Q41C F-actin (3.5 μM) than the unoxidized control. Note the absence of unbound cofilin (at 2.5 and 3.5 μM concentration) in the supernatants of its complexes with ox-actin in contrast to the complexes with unoxidized actin. Example of the SDS-PAGE gel under reducing conditions is shown (Coomassie staining). After Mical oxidation and pelleting (P) with cofilin, Q41C actin cross-linking was reversed in the presence of 2-mercaptoethanol and it now appears as a single band on the gel (compare to (b, right)). Note, that judging by the absence of actin in supernatants (S), complete C41-C374 cross-linking produces actin polymers that are disassembly-resistant despite their full oxidation and cofilin presence. Enhanced cofilin binding to the oxidized Q41C-XL (compared to unoxidized) was observed at three different ratios of cofilin:actin (0.7:1; 1:1; 2:1). The ratio used in Fig. 4d, e (1:1) is indicated with the red arrows. (e) Co-sedimentation indicates improved binding of human cofilin-1 to Mical-oxidized ANP cross-linked skeletal F-actin (30% ox-actin) compared to the unoxidized ANP cross-linked F-actin. Unoxidized and Mical-oxidized ANP-cross-linked F-actin was pelleted at high speed and analysed as described in the Methods. Conditions: [ANP-cross-linked F-actin] = 3.5 μM, [Cofilin] = 3.5 μM; Buffer: 20 mM imidazole, pH 6.8, 2 mM MgCl2, 0.2 mM EGTA, 150 mM KCl, 0.2 mM ATP, 0.5 mM DTT. Mean ± s.d. (n = 4 independent experiments per condition); the result of Student’s t-test (two-tailed) is shown (P = 0.001). See also Supplementary Fig. 7 for uncropped gels of (b–d).

Supplementary Figure 6 Further analysis of Cofilin’s effects on Mical and Semaphorin/Plexin-mediated F-actin/cellular remodeling in vivo.

(a) Knockdown of cofilin specifically in bristles using an RNAi transgenic line specific for cofilin/twinstar suppresses Mical-induced F-actin reorganization/bristle branching. Compare with Fig. 5g. Mean ± s.e.m. Student’s t-test (two-tailed); ∗∗∗∗P < 0.0001. n = 20 animals per genotype. Replicated in at least 2 independent experiments (separate crosses) per genotype. (b) Increasing the levels of Plexin (Plexin A [PlexA]) in bristles generates bristle branching7. Decreasing the levels of cofilin (cofilin/twinstar heterozygote genetic background) suppresses these Plexin-induced F-actin reorganization/bristle branching effects. Percent of flies with branched bristles. Chi-Square Test; ∗∗∗∗P < 0.0001. n = 40 animals per genotype. Replicated in at least 2 independent experiments (separate crosses) per genotype. (c) Increasing the levels of both Plexin and Mical within bristles generates increased F-actin remodeling/bristle branching in a Semaphorin-dependent manner7, and these Semaphorin/Plexin/Mical-dependent effects are suppressed by decreasing the levels of cofilin (cofilin/twinstar heterozygote genetic background). Mean ± s.e.m., Student’s t-test (two-tailed); ∗∗∗∗P < 0.0001. n = 20 animals per genotype. Mean + standard error of the mean (s.e.m.). Replicated in at least 2 independent experiments (separate crosses) per genotype. (d) Knockdown of cofilin specifically in neurons using the ELAV-GAL4 driver and an RNAi transgenic line specific for cofilin/twinstar generates motor axon guidance defects similar to those described in Fig. 6b, c. n = 100 hemisegments assessed in 10 animals per genotype, Chi-Square Test; ∗∗∗∗P < 0.0001. All genotypes in a-d are heterozygous (B11-GAL4/+, ELAV-GAL4/+, UAS:Mical/+, UAS:PlexA/+, tsr/+, and/or cofilin RNAi/+). The twinstar (tsr) RNAi knockdown lines employed were tsrHMS00534 (obtained from the Bloomington Drosophila Stock Center) and tsrKK108706 (obtained from the Vienna Drosophila Resource Center). The UAS:HAPlexA and UAS:Mical lines were as previously described1,4,7. Other lines were as described in Figs 5 and 6.

Supplementary Figure 7 Uncropped gels.

Uncropped gels for Fig. 1d (a, red boxes), 1i (b), 2a (c), 2b [upper] (d, red boxes), 2b [lower] (e, red boxes), 2c [upper] (f), 2c [lower] (g, red boxes), 2d (h), 3a, b [inserts] (i, red boxes), 3f (j, red boxes), 4d (k, red boxes), Supplementary Figs 2a (l), 2c (m, red boxes), 2d [upper left] (n), 2d [lower left] (o), 2d [upper middle and right] (p), 2d [lower middle and right] (q), 2e (r, red boxes), 2f [upper] (s), 2f [lower] (t), 5b (u, red boxes), 5c (v, red boxes), and 5d (w).

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Supplementary Table 1

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Cofilin severing of unoxidized actin filaments.

Conditions: [Rabbit skeletal actin-Cy3b-maleimide] = 1 μM, [human cofilin-1] = 100 nM. Bar = 10 μm. Recording started 90 s after cofilin addition to the flow chamber. See also Fig. 4b, c. (AVI 3551 kb)

Cofilin severing of the 11% copolymer formed from Mical-oxidized and unoxidized actin.

Dramatic acceleration of cofilin-mediated F-actin severing was observed in copolymer compared to the unoxidized control (Supplementary Movie 1, also see Fig. 4b, c). Conditions: [Rabbit skeletal actin-Cy3b-maleimide] = 1 μM, [human cofilin-1] = 100 nM. Bar = 10 μm. Recording started 90 s after cofilin addition to the flow chamber. (AVI 2213 kb)

Cofilin-mediated F-actin severing is enhanced by an increase in the percentage of Mical-oxidized actin in the copolymer: 11% copolymer.

Cofilin severing of the 11% copolymer of Mical-oxidized actin is slower compared to that of the 28% copolymer (compare with Supplementary Movie 4). Conditions: [Rabbit skeletal actin-Cy3b-maleimide] = 1 μM, [human cofilin-1] = 50 nM. Bar = 10 μm. Recording started 90 s after cofilin addition to the flow chamber. (AVI 1566 kb)

Cofilin-mediated F-actin severing is enhanced by an increase in the percentage of Mical-oxidized actin in the copolymer: 28% copolymer.

Cofilin severing of the 28% copolymer of Mical-oxidized and unoxidized actin is greatly accelerated compared to that of the 11% copolymer (compare with Supplementary Video 3). Note, that filaments appear severed already at the beginning of the recording. Conditions: [Rabbit skeletal actin-Cy3b-maleimide] = 1 μM, [human cofilin-1] = 50 nM. Bar = 10 μm. Recording started 90 s after cofilin addition to the flow chamber. (AVI 1648 kb)

Cofilin recruitment to unoxidized actin filaments.

Small clusters of cofilin are formed on actin filaments upon co-polymerization. Rabbit skeletal actin-Alexa488SE (green) and yeast cofilin-KCK-Cy5-maleimide (red). Conditions: [Actin] = 0.6 μM, [cofilin] = 38.5 nM. Bar = 10 μm. Data quantified in Supplementary Fig. 4. (AVI 1346 kb)

Enhanced cofilin recruitment to the copolymer formed from Mical-oxidized (11%) and unoxidized actin.

Note, that clustering of cofilin on actin filaments is enhanced compared to that on unoxidized actin control (compare with Supplementary Video 5). The greater number of actin filaments per field (compared to the unoxidized control;Supplementary Video 5) is also consistent with the enhanced severing of the copolymer by cofilin (and supports the data shown in Supplementary Fig. 3b–d). Rabbit skeletal actin-Alexa488SE (green) and yeast cofilin-KCK-Cy5-maleimide (red). Conditions: [Actin] = 0.6 μM, [cofilin] = 38.5 nM. Bar = 10 μm. Data quantified in Supplementary Fig. 4. (AVI 1839 kb)

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Grintsevich, E., Yesilyurt, H., Rich, S. et al. F-actin dismantling through a redox-driven synergy between Mical and cofilin. Nat Cell Biol 18, 876–885 (2016). https://doi.org/10.1038/ncb3390

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