The hydrolysis of ATP during actin polymerization has been postulated to alter filament structure(1, 2, 3, 4) , change the kinetics of monomer binding(5, 6) , and modulate the association of actin binding proteins(7, 8, 9) . Biochemical evidence suggests that ATP hydrolyzes rapidly as monomers add to the end of a filament, but that subsequent release of hydrolysis products is slow(10) . In F-actin ()at steady state, ADP is bound within the nucleotide binding pocket of the actin monomer(11) , and this nucleotide is trapped until the monomer dissociates from the filament(5, 12) . However, the inorganic phosphate (P) generated dissociates slowly from the filament without monomer turnover (13) . Therefore, newly polymerized filaments will be rich in the hydrolysis intermediate ADP-P while older filaments will contain predominantly ADP(14) .

Inorganic phosphate binds to the actin filament at a low affinity (mM) site (15) postulated to be one of two sites occupied by P released from ATP upon hydrolysis(16, 17) . Binding of P to F-ADP actin reduces the off-rate of monomers from the fast-exchanging (barbed) end of filaments(6) . The changes in actin monomer-filament interactions may be due to alterations in filament structure. The electron density map of the actin filament alters when P is bound, with domain 2 of the actin monomer moving out from the helical center of the filament and away from domain 1 of the next monomer in the two start helix(3) . In contrast, this domain is not readily visualized in F-actin polymerized from ADP monomers, suggesting its position is variable.

AlF and BeF (the terms P, AlF, and BeF indicate that the exact ionic species is unknown) have effects similar to P on the actin filament. Although the exact isoform of AlF and BeF is unclear(18) , these agents reduce the off-rates of monomers, change the structure of the filament(3, 19) , and alter the filament's susceptibility to proteolysis(20) . BeF binds with higher affinity to F-actin than does P, and its association and dissociation rate constants are much slower, a finding that suggests it may bind to the high-affinity P site within the nucleotide binding site of the monomer(17) .

The ATP hydrolysis that accompanies actin polymerization has been suggested to enhance the disassembly of filaments at a time separate from that of assembly(21) . This hypothesis implies that the rate of ATP hydrolysis and release of P can act as a clock, with the age of a filament given by the relative concentrations of ATP, ADP-P, and ADP subunits. We report that the actin filament severing protein gelsolin can differentiate between ADP-P and ADP-rich filaments, with filaments in the ADP-P state being severed by gelsolin much more slowly. Binding of P, AlF, or BeF reduces the extent of severing by both intact gelsolin and its Ca insensitive N-terminal domain. These findings suggest that in cells the assembly and disassembly of filaments could be regulated not only by signal transduction pathways, but by the energy charge of the cell and the age of pre-existing actin filaments.

MATERIALS AND METHODS

BeSO and Al(SO) were purchased from Aldrich. Phalloidin, tetramethylrhodamine isothiocyanate-coupled phalloidin (TRITC-phalloidin), NaF, nucleotides, and all other buffers and salts were purchased from Sigma.

Proteins

F-ADP-actin was polymerized at concentrations of 15 to 30 µM in solutions containing 150 mM KCl, 20 mM HEPES, pH 7.4, 0.5 mM ADP, 0.2 mM dithiothreitol, 2 mM MgCl, and 0.2 mM CaCl. F-ADP-P actins were generated by polymerization of G-ADP actin in similar solutions containing various concentrations of KHPO and KHPO (varied to give the appropriate pH) as indicated under ``Results,'' and KCl, with a total K concentration equal to 150 mM(15) .

BeF and AlF were generated by addition of BeSO and NaF, or Al(SO) and NaF, at a molar ratio of 1 aluminum or beryllium to 4 NaF, to a modified polymerization solution containing 100 mM KCl, 50 mM HEPES, pH 7.4, 0.2 mM CaCl, 2 mM MgCl, 0.5 mM ADP, and 0.2 mM dithiothreitol. The final BeF or AlF concentrations stated in the text were taken from the concentration of beryllium or aluminum added to the buffer.

Human plasma gelsolin was purified by elution from DE-52 ion exchange matrix in 30 mM NaCl, 3 mM CaCl, 25 mM Tris, pH 7.4, as described by Kurokawa et al.(24) , dialyzed into 75 mM NaCl, 20 mM Tris, pH 7.4, and 0.2 mM EGTA, rapidly frozen in liquid nitrogen and stored at -80 °C. Gelsolin concentration was determined from the absorbance at 280 nm using the extinction coefficient 1.8 ml mg cm. The N-terminal fragment of gelsolin, s1-3, was purified from Escherichia coli as described(25) .

Severing Assay

where I is the fluorescence at time t, I is the fluorescence of TRITC-phalloidin in the absence of actin, and I is the fluorescence of the TRITC-phalloidin F-actin mixture.

While the kinetics of gelsolin severing TRITC-phalloidin-bound F-actin depend on divalent cation concentrations (27) the severing by gelsolin s1-3 was found to be completely independent of the presence of divalent cations, as previously reported(25) . For experiments using intact gelsolin, the Ca concentration was measured as described previously (27) using Mag Fura 5 (Molecular Probes, Eugene, OR).

RESULTS

Using gelsolin's ability to displace phalloidin from F-actin and the enhanced fluorescence of TRITC-phalloidin upon binding to actin as a severing assay(27) , we investigated whether the binding of P to F-ADP actin alters actin's susceptibility to severing. Reduction of free Ca by P was accounted for by titration of [Ca] in control buffers with EGTA. Ca concentrations were measured using the ratiometric dye Mag Fura 5, as described previously(27) .

Fig. 1demonstrates that binding of P to F-ADP actin reduces the extent of severing by human plasma gelsolin. F-ADP actin was incubated overnight in buffers containing increasing concentrations of P, diluted in identical buffers containing TRITC-phalloidin and allowed to come to equilibrium (as determined from the increased emission of TRITC-phalloidin). Addition of gelsolin reduced the fluorescence to baseline levels, as previously reported. Gelsolin displaced all the TRITC-phalloidin from F-ADP actin within 5 min at all but the lowest Ca concentration. In contrast, F-ADP-P actins showed a P concentration-dependent resistance to severing by gelsolin within this time scale. This result suggests that binding of P to F-ADP actin generates filaments resistant to gelsolin. However, to escape complications from the alterations in free Ca by P, we continued these studies using bacterially expressed N-terminal gelsolin fragment s1-3, which is Ca insensitive(25) .

Figure 1: Gelsolin severs F-ADP-P actin less effectively than it does F-ADP actin. 40 µM G-ADP actin was polymerized overnight in either F-ADP buffer, pH 7.4, or F-ADP buffer containing various concentrations of P, pH 7.4, as described under ``Materials and Methods.'' The increase in fluorescence of 1 µM TRITC-phalloidin in F-ADP and F-ADP-P buffers was measured upon addition of 400 nM F-actin and found to be identical for both ADP and ADP-P F-actins (data not shown). Addition of 200 nM human plasma gelsolin displaced all the TRITC-phalloidin within 5 min from F-ADP actin (open circles) at all but the lowest Ca concentration. Addition of 200 nM gelsolin to F-ADP-P actins (closed circles, P concentration indicated to the right of the data point) consistently displaced less of the TRITC-phalloidin than that observed for F-ADP at equivalent Ca concentrations. Free Ca was determined as described under ``Materials and Methods.''

Phosphate Binding to F-ADP Actin Inhibits Severing by Gelsolin s1-3

Figure 2: F-ADP-P actin is resistant to severing by gelsolin s1-3. ADP actin was polymerized overnight at 30 µM in the presence of either 150 mM KCl or 50 mM KHPO, pH 6.8, 100 mM KCl; with 10 mM HEPES, 2 mM MgCl2, 0.5 mM ADP; 0.2 mM dithiothreitol. F-actin was diluted to 300 nM in the above buffer containing 1 µM TRITC-phalloidin. Subsequent addition of 180 nM gelsolin s1-3 displaced all the phalloidin from F-ADP actin (open circles) as indicated by the complete loss of enhanced fluorescence, yet displaced only 40% of that bound to F-ADP-P actin (closed circles). Addition of gelsolin s1-3 at 360 nM (closed squares) or 540 nM (closed triangles) did not increase the amount of TRITC-phalloidin displaced on this time scale.

Gelsolin interacts with the phosphates of phosphoinositide lipids(28) , and with ATP(29) . However, it appears unlikely that the effect of P is on gelsolin rather than actin. Increasing concentrations of gelsolin s1-3 do not lead to an increased loss of F-actin (Fig. 2), consistent with decreased substrate availability. Also, incubation of gelsolin s1-3 in 50 mM P buffer before addition to TRITC-phalloidin-bound F-ADP actin led to complete severing which could not be distinguished from controls (data not shown).

A previous study demonstrated a binding site for the HPO ion (15) on F-ADP actin, based on the apparently tighter binding at pH 6.8 compared with pH 8.0, where the HPO ion is more prevalent. We used a similar approach to define the specific phosphate ion involved in generating gelsolin-resistant actin by determining the phosphate concentration and pH dependence of inhibition of severing by gelsolin s1-3. Consistent with the results using human plasma gelsolin, generation of F-actin resistant to severing by gelsolin s1-3 requires tens of millimolar P at pH 6.8 (Fig. 3). In contrast, at pH 8.0, 50% inhibition is detected at 12 mM P, and 25 mM maximally reduces severing. These results suggest that it is the binding of HPO, not HPO, which generates the severing-resistant state. However, we cannot exclude a more complex mechanism by which the binding of both ions generates the severing resistant state.

Figure 3: Concentration and pH dependence of the inhibitory effect of P on the severing of F-actin by gelsolin s1-3. G-ADP actin was polymerized in buffers that differed in their P concentration and pH. KCl was varied such that the total K concentration was 150 mM. 400 nM actin was diluted into buffers containing 1 µM TRITC-phalloidin and the increase in fluorescence upon binding was measured. The increase in fluorescence was similar for all samples and was normalized to 1.0 as described under ``Materials and Methods.'' 200 nM gelsolin s1-3 was added and the loss of fluorescence followed over time. The concentration dependence is altered, with lower concentrations showing inhibitory activity at higher pH. Time is in seconds.

Binding of P to F-ADP actin, as indicated in Fig. 3, causes a dramatic reduction in the extent of severing, when assayed over a relatively short period of time. However, even at 50 mM P, pH 8.0, there is some small amount of fluorescence loss on this time scale. To address whether the inhibition observed was actually a reduction in the kinetics of severing, we continued the analysis over a longer time scale. As illustrated in Fig. 4, gelsolin will sever ADP-P F-actin, but requires thousands of seconds to do so. It should also be noted that the loss of fluorescence is not well described by a single exponential function.

Figure 4: Severing of ADP-P actin by gelsolin s1-3 goes to completion, but with much slower kinetics. Severing of 400 nM F-ADP (closed circles) or F-ADP-P actin (open circles; 50 mM P, pH 8.0, F-buffer) by 200 nM gelsolin s1-3 was followed over a longer time scale. Complete loss of fluorescence was defined as that lost by F-ADP actin in the presence of excess gelsolin s1-3. Time is in seconds.

Effects of Berylium Fluoride and Aluminum Fluoride

Figure 5: Low concentrations of AlF and BeF generate F-actin resistant to severing. In the top panel, G-ADP actin was polymerized in the presence of various concentrations of BeSO and NaF to give the concentration of BeFindicated in the panel. F-actin was diluted to a final concentration of 300 nM in buffer containing 1 µM TRITC-phalloidin and a concentration of BeF equal to that of the polymerization buffer. The TRITC-phalloidin was allowed to bind for 5 min. 300 nM gelsolin s1-3 was added at 0 s. The final fluorescence after addition of gelsolin s1-3 to F-ADP actin was 68 to 69 fluorescence units and was equal to the fluorescence of 1 µM TRITC-phalloidin in the absence of F-actin. The bottom panel illustrates a similar experiment, except that G-ADP-actin was polymerized and analyzed in various concentrations of AlF, generated as described under ``Materials and Methods.'' The concentration of AlF is indicated to the right of the relevant curve. Time is in seconds.

Binding of BeF to F-ADP actin reduces the fluorescence of pyrene iodoacetamide-labeled F-ADP actin(17) . Incubation of 10 µM F-PIA-ADP actin with either 10 or 100 µM BeF depresses the pyrene fluorescence with a second order rate constant of approximately 20 M s (Fig. 6A). The extent and kinetics of fluorescence depression are similar to those previously reported(17) . In contrast, 1 mM BeF caused an increase in fluorescence of F-PIA actin, not a decrease, with a rate constant of approximately 1 M s. This increase in the fluorescence of F-PIA ADP actin upon exposure to BeF concentrations greater than 100 µM was quite apparent in an independent experiment examining equilibrium effects (Fig. 6B). These results provide further evidence for two BeF binding sites on F-ADP actin.

Figure 6: The effects of BeF on the fluorescence of F-PIA-ADP actin indicate the presence of two binding sites for this molecule on F-ADP actin. In panel A, the kinetics of the fluorescence change of 10 µM F-PIA-ADP actin were measured upon addition of BeFconcentrations of 0.01 (open circles), 0.1 (closed circles), and 1 mM (open squares). Only every 10th data point is plotted for clarity. The line indicates the change in fluorescence fit to a second order rate constant of 20 M s for 10 and 100 µM BeF, and 1 M s for 1 mM BeF. In a separate experiment (panel B) the fluorescence change of 10 µM F-ADP-PIA after exposure to various concentrations of BeF for 24 h is illustrated.

Inhibition of severing by AlF requires higher concentrations than BeF. As illustrated in Fig. 5B, 100 µM AlF has little effect on the rate of severing, while 0.5 mM shows a significant reduction. In contrast to BeF, AlF did not show a reduction in inhibitory activity within the concentration range tested. The concentration dependence of AlF action is consistent with previous reports comparing the ability of AlF and BeF to recreate the ADP-P like state on F-actin(17) .

AlF and BeF do not appear to affect gelsolin directly. Incubation of gelsolin s1-3 in maximally inhibitory concentrations of AlF, BeF, or P followed by dilution into buffer lacking these molecules had no effect on the kinetics and extent of severing (data not shown). This result is not due to rapid dissociation of the ion from gelsolin. Gelsolin s1-3 severed F-ADP actin incubated for 5 min in the presence of 1 mM AlF, with kinetics similar to that observed in the absence of AlF (Fig. 7). In contrast, overnight incubation of F-ADP actin in 1 mM AlF strongly reduced the susceptibility to severing by gelsolin s1-3. This result, and the fact that increasing gelsolin s1-3 concentration does not increase the amount of ADP-P actin severed (Fig. 1) strongly suggest that the target of these agents is the actin filament, not gelsolin.

Figure 7: Incubation of F-ADP actin in 1 mM AlF does not rapidly lead to the generation of severing resistant F-actin. The severing of F-ADP actin in two control experiments (open symbols) is compared with that of G-ADP actin polymerized overnight in 1 mM AlF and assayed in 1 mM AlF (closed triangles) and with that of F-ADP actin incubated in 1 mM AlFfor 5 min and then assayed in 1 mM AlF(closed squares). The F-actin and gelsolin s1-3 concentrations were 300 nM each. Time is in seconds.

DISCUSSION

A significant fraction of cellular ATP metabolism is associated with polymerization of actin(30) , yet the function of actin's polymerization-stimulated ATPase is unclear. ATP hydrolysis is not necessary for polymerization, since ADP-G actin will polymerize(10) . Several potential roles for ATP hydrolysis have been suggested, including regulating the structure of the actin filament(1, 2, 3, 4, 31) , regulating interactions with actin binding proteins(7, 8, 32, 33) , and regulating the dynamics of monomer and filament interaction(6, 34) , effects which are not necessarily mutually exclusive.

While the exact role of ATP hydrolysis in actin dynamics remains unclear, there is some agreement on the mechanistic details. Association of G-ATP actin monomer with a filament end is rapidly followed by hydrolysis of the ATP(35) . However, the release of hydrolysis products is relatively slow, with ADP released upon monomer dissociation from the filament and the P generated from hydrolysis released at a rate approximately 2 orders of magnitude slower than ATP hydrolysis(13) . Rapid polymerization or elongation of actin filaments would produce domains within individual filaments preferentially enriched in ATP, ADP-P, and ADP. Under cellular conditions ATP hydrolysis by actin is postulated to be a vectorial, not stoichastic, process(36) . Therefore, domains enriched in ADP-P or ADP would be large and continuous, rather than dispersed throughout the filament length.

Several protein families have been proposed to regulate or enhance the disassembly of actin filaments in cells. The work described here and elsewhere suggests that members of both the gelsolin and the cofilin/destrin families of severing proteins cannot sever ADP-P-rich F-actin(37) . Furthermore, the presence of P on the actin filament dramatically reduces monomer dissociation(6, 38) , preventing the disassembly of actin filaments by the monomer sequestering proteins found in cells. We speculate that in cells the activation of actin filament disassembly by filament severing and monomer sequestering proteins is regulated in part by the relative proportions of ADP and ADP-P bound to the filament. These species, in turn, depend on the age of the actin filament and the energy charge of the cell.

The binding to F-actin of BeF, AlF, and to a lesser degree P increases the stability of the actin filament, raising the denaturation temperature from 65 °C to as high as 82 °C(4) . Similarly, 10 mM P reduces the susceptibility of filaments to denaturation by SDS or KI(39) . One mechanism by which the multiple effects of creating P-rich domains on actin filaments can be explained is by the alteration of actin filament structure(1) . Binding of P, BeF, or AlF alters the position of subdomain 2 of the actin monomer in the actin filament(3, 19) . In the ADP-P state this domain interacts strongly with the next monomer along the long pitch helix in the filament. In the absence of bound P, this domain either has multiple orientations, or is fixed in a position that interacts weakly if at all with the next monomer(3) .

The structural difference between ADP-actin and ADP-P-actin can account for the reduced dissociation of actin monomers from the filament and the reduced ability of severing molecules to disrupt the filament. Monomer dissociation requires the coordinate disruption of multiple contacts with other monomers in the filament. Increasing the number of these contacts reduces the probability of dissociation. Furthermore, gelsolin has been suggested to sever actin filaments by interrupting the actin-actin contacts along the long-pitch helix of the filament(40) . Enhancing the strength of these contacts through the increased interaction of subdomain 2 of one monomer with subdomain 1 of the next (3) should make it more difficult to sever the filament.

The binding of P and BeF to F-ADP actin has been characterized(3, 15, 16, 17, 20) . Direct measurements demonstrate a binding site for HPO with an affinity of several millimolar(15) . Similarly, BeF (exact stoichiometry unknown) has been reported to bind F-ADP actin with a K of 30 µM(17) . These two molecules compete with each other for binding to F-ADP actin(17) . However, these results do not preclude potential lower affinity binding sites for these molecules. The binding of HPO to a site on F-ADP actin is consistent with its effects on the off-rate of monomers (6, 15) and the inhibition of small molecular weight severing proteins like actophorin(37) . However, the pH sensitivity and concentration dependence of severing inhibition reported here is more consistent with the binding of HPO to F-ADP actin. Furthermore, the presence of two binding sites for P-like molecules on the actin filament is supported by the bimodal effects of BeF on the fluorescence of F-PIA-ADP actin.

The data presented here and in previously published work provide evidence of binding sites for both HPO and HPO, or their BeF equivalents, on the actin filament. These two sites would be sequentially filled in the release of P generated by ATP hydrolysis upon actin polymerization. In such a reaction HPO is released upon ATP hydrolysis, where it remains bound in the nucleotide pocket until titrated to HPO, which is slowly released from the actin filament. Consistent with both previous and current speculations, BeF was hypothesized to bind the P binding site first occupied upon nucleotide hydrolysis(18) . Resistance of F-actin to severing by gelsolin correlates both with saturation of the high affinity BeF site and with binding to a low-affinity, at physiological pH, P site. In the context of actin turnover in the cell, newly polymerized actin filaments would first become sensitive to severing by gelsolin once HPO is titrated to HPO, but degradation by cofilin-like molecules and by monomer sequestering proteins would require HPO dissociation.

The hypothesis that F-actin has binding sites for both HPO and HPO, which fill sequentially upon ATP hydrolysis during polymerization and which modulate the association and activities of different actin binding proteins has implications for the turnover of actin filaments in cells. Newly polymerized actin filaments, rich in HPO would be resistant to severing and depolymerization. Titration of HPO to HPO would allow severing by gelsolin-like molecules, but this shortened filament would be relatively resistant to disassembly by cofilin-like molecules and to depolymerization. This gelsolin capped filament would then have some time, based on the dissociation rate of HPO, to move to a new site in the cell, where it could uncap or incorporate into new cytoskeletal structures. If the filament is not stabilized, either by further elongation with accompanying ATP hydrolysis, or by association of other stabilizing factors such as tropomyosin, the time-dependent loss of HPO increases the probability of further fragmentation by cofilin-like molecules and depolymerization by monomer dissociation.

This model adds a temporal component to the many previous models that considered actin turnover in the context of the spatial organization of the cell. Several studies of actin turnover in cells suggest that actin filament depolymerization is not a spatially uniform process(41, 42) , but the mechanism for locally altering depolymerization is undefined. Consideration of the effects of nucleotide hydrolysis by actin on filament severing and depolymerization suggests that the dynamics of filament turnover in cells are defined by the ATPase rate of actin and the titration and release of P, as well as the regulated action of actin binding proteins.

FOOTNOTES

*

This work was done during the tenure of a Research Fellowship and supported by Grant-in-Aid 13-502-945 (to P. G. A.) from the American Heart Association, Massachusetts Affiliate, Inc. Further support came in part from National Institutes of Health Grant AR 38910 (to P. A. J.) and National Institutes of Health Training Grant HL 07680 (to T. P. Stossel). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked ``advertisement'' in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

§

To whom correspondence should be addressed: Div. of Experimental Medicine, L. M. R. C 301, Brigham and Women's Hospital, 221 Longwood Ave., Boston, MA 02115. Tel.: 617-278-0390; Fax: 617-734-2248; pallen{at}calvin.bwh.harvard.edu.

()

The abbreviations used are: F-actin, filamentous actin; G-actin, monomeric actin; PIA, pyrene iodoactamide; P, inorganic phosphate; ADP-P, the nucleotide state in which hydrolysis has occurred but release of products has not; AlF, aluminum fluoride, exact ionic species unknown; BeF, berrylium fluoride, exact ionic species unknown; s1-3, N-terminal truncate of human plasma gelsolin containing domains 1-3 of the parent molecule; TRITC, tetramethylrhodamine isothiocyanate.

ACKNOWLEDGEMENTS

REFERENCES

1. Nonomura, Y., Katayama, E., and Ebashi, S. (1975) J. Biochem. (Tokyo) 78, 1101-1104
2. Janmey, P. A., Hvidt, S., Oster, G. F., Lamb, J., Stossel, T. P., and Hartwig, J. H. (1990) Nature 347, 95-99 [CrossRef][Medline] [Order article via Infotrieve]
3. Orlova, A., and Egelman, E. H. (1992) J. Mol. Biol. 227(4), 1043-1053
4. Nikolaeva, O. P., Dedova, I. V., Khvorova, I. S., and Levitsky, D. I. (1994) FEBS Lett. 351, 15-18 [CrossRef][Medline] [Order article via Infotrieve]
5. Cooke, R. (1975) Biochemistry 14, 3250-3266 [CrossRef][Medline] [Order article via Infotrieve]
6. Rickard, J. E., and Sheterline, P. (1986) J. Mol. Biol. 191, 273-280 [CrossRef][Medline] [Order article via Infotrieve]
7. Laham, L. E., Lamb, J. A., Allen, P. G., and Janmey, P. A. (1993) J. Biol. Chem. 268, 14202-14207 [Abstract/Free Full Text]
8. Maciver, S. K., and Weeds, A. G. (1994) FEBS Lett. 347, 251-256 [CrossRef][Medline] [Order article via Infotrieve]
9. Carlier, M. F. (1992) Philos. Trans. R. Soc. Lond. B Biol. Sci. 336, 93-97 [CrossRef][Medline] [Order article via Infotrieve]
10. Korn, E. D., Carlier, M. F., and Pantaloni, D. (1987) Science 238, 638-644 [Abstract/Free Full Text]
11. Straub, F. B., and Feuer, G. (1950) Biochim. Biophys. Acta 4, 455-470 [CrossRef]
12. Pantaloni, D., Carlier, M. F., Coue, M., Lal, A. A., Brenner, S. L., and Korn, E. D. (1984) J. Biol. Chem. 259, 6274-6283 [Abstract/Free Full Text]
13. Carlier, M. F. (1987) Biochem. Biophys. Res. Commun. 143, 1069-1075 [CrossRef][Medline] [Order article via Infotrieve]
14. Dufort, P. A., and Lumsden, C. J. (1993) Biophys. J. 65, 1757-1766 [Medline] [Order article via Infotrieve]
15. Carlier, M. F., and Pantaloni, D. (1988) J. Biol. Chem. 263, 817-825 [Abstract/Free Full Text]
16. Wanger, M., and Wegner, A. (1987) Biochim. Biophys. Acta 914, 105-113 [CrossRef][Medline] [Order article via Infotrieve]
17. Combeau, C., and Carlier, M. F. (1988) J. Biol. Chem. 263, 17429-17436 [Abstract/Free Full Text]
18. Combeau, C., and Carlier, M. F. (1989) J. Biol. Chem. 264, 19017-19021 [Abstract/Free Full Text]
19. Lepault, J., Ranck, J. L., Erk, I., and Carlier, M. F. (1994) J. Struct. Biol. 112, 79-91 [CrossRef][Medline] [Order article via Infotrieve]
20. Muhlrad, A., Cheung, P., Phan, B. C., Miller, C., and Reisler, E. (1994) J. Biol. Chem. 269, 11852-11858 [Abstract/Free Full Text]
21. Pollard, T., Goldberg, I., and Schwarz, W. (1992) J. Biol. Chem. 267, 20339-20345 [Abstract/Free Full Text]
22. Spudich, J., and Watt, S. (1971) J. Biol. Chem. 246, 4866-4871 [Abstract/Free Full Text]
23. Lamb, J. A., Allen, P. G., Tuan, B. Y., and Janmey, P. A. (1993) J. Biol. Chem. 268, 8999-9004 [Abstract/Free Full Text]
24. Kurokawa, H., Fujii, W., Ohmi, K., Sakurai, T., and Nonomura, Y. (1990) Biochem. Biophys. Res. Commun. 168, 451-457 [CrossRef][Medline] [Order article via Infotrieve]
25. Way, M., Gooch, J., Pope, B., and Weeds, A. G. (1989) J. Cell Biol. 109, 593-605 [Abstract/Free Full Text]
26. Huang, Z., Haugland, R. P., You, W., and Haugland, R. P. (1992) Anal. Biochem. 200, 199-204 [CrossRef][Medline] [Order article via Infotrieve]
27. Allen, P. G., and Janmey, P. A. (1994) J. Biol. Chem. 269, 32916-32923 [Abstract/Free Full Text]
28. Janmey, P. A., and Stossel, T. P. (1987) Nature 325, 362-364 [CrossRef][Medline] [Order article via Infotrieve]
29. Yamamoto, H., Ito, H., Nakamura, H., Hayashi, E., Kishimoto, S., Hashimoto, T., and Tagawa, K. (1990) J. Biochem. 108, 505-506 [Abstract/Free Full Text]
30. Verhoeven, A. J., Cook, C. A., and Holmsen, H. (1988) Anal. Biochem. 174, 672-688 [CrossRef][Medline] [Order article via Infotrieve]
31. Ikeuchi, Y., Iwamura, K., Machi, T., Kakimoto, T., and Suzuki, A. (1992) J. Biochem. (Tokyo) 111, 606-613
32. Carlier, M. F., Jean, C., Rieger, K. J., Lenfant, M., and Pantaloni, D. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 5034-5038 [Abstract/Free Full Text]
33. Perelroizen, I., Carlier, M. F., and Pantaloni, D. (1995) J. Biol. Chem. 270, 1501-1508 [Abstract/Free Full Text]
34. Carlier, M. F., Pantaloni, D., and Korn, E. D. (1985) J. Biol. Chem. 260, 6565-6571 [Abstract/Free Full Text]
35. Carlier, M. F. (1990) Adv. Biophys. 26, 51-73 [CrossRef][Medline] [Order article via Infotrieve]
36. Carlier, M. F., Pantaloni, D., and Korn, E. D. (1986) J. Biol. Chem. 261, 10785-10792 [Abstract/Free Full Text]
37. Maciver, S. K., Zot, H. G., and Pollard, T. D. (1991) J. Cell Biol. 115, 1611-1620 [Abstract/Free Full Text]
38. Wendel, H., and Dancker, P. (1986) Biochim. Biophys. Acta 873, 387-396 [CrossRef][Medline] [Order article via Infotrieve]
39. Dancker, P., and Fischer, S. (1989) Z. Naturforsch. C 44, 698-704
40. McLaughlin, P. J., Gooch, J. T., Mannherz, H. G., and Weeds, A. G. (1993) Nature 364, 685-692 [CrossRef][Medline] [Order article via Infotrieve]
41. Symons, M. H., and Mitchison, T. J. (1991) J. Cell Biol. 114, 503-513 [Abstract/Free Full Text]
42. Small, J. V., Herzog, M., and Anderson, K. (1995) J. Cell Biol. 129, 1275-1286 [Abstract/Free Full Text]

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				L. R. Otterbein, P. Graceffa, and R. Dominguez The Crystal Structure of Uncomplexed Actin in the ADP State Science, July 27, 2001; 293(5530): 708 - 711. [Abstract] [Full Text] [PDF]

				L. D. Belmont, A. Orlova, D. G. Drubin, and E. H. Egelman A change in actin conformation associated with filament instability after Pi release PNAS, January 5, 1999; 96(1): 29 - 34. [Abstract] [Full Text] [PDF]

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