Structures of microfilament destabilizing toxins bound to actin provide insight into toxin design and activity

Allingham, John S.; Zampella, Angela; D’Auria, Maria Valeria; Rayment, Ivan

doi:10.1073/pnas.0502089102

Cited by 87 publications

(80 citation statements)

References 25 publications

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“…Two subsequent studies have led to additional independent crystal forms of actin in which the monomers are again related by pure translation in the longitudinal direction with an interface similar to that described earlier (Allingham et al, 2005;Rizvi et al, 2006). Finally, another actin structure has been reported in which two actin monomers are present in one asymmetric unit of the crystal (Klenchin et al, 2006).…”

Section: Introductionmentioning

confidence: 85%

“…One coordinate set was obtained from the crystal structure of the cross-linked actin dimer reported previously (Kudryashov et al, 2005); this crystal is isomorphous with one obtained from a noncross-linked actin mutant in complex with either ATP or ADP (Rould et al, 2006). Four other coordinate sets were obtained from structures in which actin monomers were not cross-linked to each other but were nonetheless seen to form a similar interface between longitudinally related monomers in the crystal (Allingham et al, 2005;Klenchin et al, 2006;Otomo et al, 2005;Rizvi et al, 2006; Table 3). These six models are derived from six independent crystal forms whose unit-cell parameters and crystal contacts (apart from those representing the longitudinal interface) are distinct.…”

Section: Comparison Of the Longitudinal Interface Observed In Multiplmentioning

confidence: 99%

See 1 more Smart Citation

Multiple crystal structures of actin dimers and their implications for interactions in the actin filament

Sawaya

Kudryashov

Pashkov

et al. 2008

Acta Crystallogr D Biol Cryst

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The structure of actin in its monomeric form is known at high resolution, while the structure of filamentous F-actin is only understood at considerably lower resolution. Knowing precisely how the monomers of actin fit together would lead to a deeper understanding of the dynamic behavior of the actin filament. Here, a series of crystal structures of actin dimers are reported which were prepared by cross-linking in either the longitudinal or the lateral direction in the filament state. Laterally cross-linked dimers, comprised of monomers belonging to different protofilaments, are found to adopt configurations in crystals that are not related to the native structure of filamentous actin. In contrast, multiple structures of longitudinal dimers consistently reveal the same interface between monomers within a single protofilament. The reappearance of the same longitudinal interface in multiple crystal structures adds weight to arguments that the interface visualized is similar to that in actin filaments. Highly conserved atomic interactions involving residues 199-205 and 287-291 are highlighted.

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Section: Introductionmentioning

confidence: 85%

Section: Comparison Of the Longitudinal Interface Observed In Multiplmentioning

confidence: 99%

Multiple crystal structures of actin dimers and their implications for interactions in the actin filament

Sawaya

Kudryashov

Pashkov

et al. 2008

Acta Crystallogr D Biol Cryst

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“…Diverse mechanisms targeting the cytoskeleton dynamics have been reported for several depolymerizing macrolide toxins that interact directly with actin. They include sequestering of G-actin to inhibit its addition to the polymer, capping the barbed-ends of actin filaments to prevent filament growth, and even severing of F-actin [27,31,35,36]. Some authors indicated that Factin disassembly induced by PTX-2 and PTX-6 was associated with an increase in G-actin [23,24].…”

Section: Discussionmentioning

confidence: 99%

Lactone Ring of Pectenotoxins: a Key Factor for their Activity on Cytoskeletal Dynamics

Ares

Louzao²,

Espiña³

et al. 2007

Cell Physiol Biochem

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Background: Pectenotoxins are a group of natural products from marine origin that can accumulate in shellfish and intoxicate humans. Recently, novel homologues such as pectenotoxin-11 (PTX-11) and pectenotoxin-2 seco acid (PTX-2SA) have been identified. Their toxic potential towards experimental animals has been evaluated however their interaction with cellular systems is almost unknown. This is the first report showing (i) the biological activity of PTX-11 and PTX-2SA on actin cytoskeleton and morphology of living cells and (ii) the structure- activity relationship for this family of toxic compounds. Methods: Fluorescent phalloidin was utilized to quantify and visualize any modification in polymerized actin. Fluorescence values were obtained with laser-scanning cytometer and cells were imaged through confocal microscopy. For structure-activity evaluations, pectenotoxin-1 (PTX-1) and pectenotoxin-2 (PTX-2) was also analyzed. Results: Data showed that PTX-11 triggered a remarkable depolymerizing effect on actin cytoskeleton and also modifications in the shape of cells. In contrast, PTX-2SA did not evidence the same effects. Conclusion: Our findings point out that (i) the actin cytoskeleton is a common target for PTX-11, PTX-2 and PTX-1, but not for PTX-2SA, and (ii) this difference in activity is related to the presence or absence of an intact lactone ring in their structures.

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“…It was then followed by an HRP-conjugated secondary antibody against mouse IgM or IgG, respectively, and chemiluminescent detection. F-actin was prepared from G-actin by adding 1/10 volume of actin polymerization buffer (500 mM KCl, 20 mM, MgCl 2 , 10 mM ATP) based on an established procedure (44).…”

Section: Methodsmentioning

confidence: 99%

Erythrocyte Tropomodulin Isoforms with and without the N-terminal Actin-binding Domain

Yao¹,

Sung

2010

Journal of Biological Chemistry

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Erythrocyte tropomodulin (E-Tmod or Tmod1) of 41 kDa is a tropomyosin (TM)-binding protein that caps the slow-growing end of the actin filaments. Its N-terminal half is flexible, whereas the C-terminal half has a single domain structure. E-Tmod/TM5 complex may function as a "molecular ruler" generating actin protofilaments of ϳ37 nm. Here we report the discovery of a short isoform of 29 kDa that lacks the N-terminal actin-binding domain (N-ABD) but retains the C-terminal actin-binding domain (C-ABD). E-Tmod29 can be generated by alternative splicing from an upstream promoter or by multiple transcriptional start sites from a downstream promoter. Promoter switching leads to a surge of E-Tmod41 in reticulocytes, which degrades quickly in the cytosol. We expressed recombinant isoforms in Escherichia coli and tested their binding toward TM5, G-actin, and F-actin. Solid-phase binding assays show that, without the N-terminal 102 residues, E-Tmod29 binds to TM5 or G-actin more strongly than E-Tmod41 does, but barely binds to F-actin after TM5 binding. Erythrocytes are responsible for the transport of O 2 and CO 2 in tissues throughout the body. Their cell membranes have a thin layer of protein skeleton under the lipid bilayer. The viscoelasticity and durability of this protein skeleton allows erythrocytes to circulate for 120 days in humans and 60 days in mice. These membrane skeletal proteins are differentially expressed during erythroid differentiation, and the complex transcellular cytoskeleton is remodeled into a membrane skeleton during reticulocyte maturation (1, 2).The membrane skeletal network consists of a large number of basic repeating units interconnected to each other. Each unit contains two kinds of major complexes, a junctional complex (JC) 3 and suspension complex (SC), located in the center and up to six in the periphery, respectively (Fig. 1). A JC includes actin, tropomyosin (TM), erythrocyte tropomodulin (E-Tmod), protein 4.1R, adducin (3), protein 4.9 (dematin), and p55 (for review see Refs. 3 and 4), with six spectrin heterodimers (Sp) radiating from the center. Associated near the distal end of each Sp is an SC. An SC consists of several proteins, including anion exchanger (band 3), ankryin, and protein 4.2, which suspends the skeletal network to the lipid bilayer (for review see Refs. 5 and 6).Some of these membrane skeletal proteins are encoded by genes known to have alternative splicing, alternative promoters, multiple transcriptional start sites, and/or multiple polyadenylation sites (7-14). Indeed, some in JC are cell type-specific isoforms generated by one or more of the above mechanisms. For example, exon 16 of protein 4.1R, which encodes the 8-kDa spectrin/actin-binding domain (ABD), is alternatively spliced (15, 16). ␤ spectrin, which has an ABD, is generated by the differential splicing of its exon 32 (9). Interestingly, ␣ spectrin, which has no ABD, is synthesized three times more than ␤ spectrin, but is quickly degraded in reticulocytes if not incorporated into the membrane skeleton (1...

show abstract

Structures of microfilament destabilizing toxins bound to actin provide insight into toxin design and activity

Cited by 87 publications

References 25 publications

Multiple crystal structures of actin dimers and their implications for interactions in the actin filament

Multiple crystal structures of actin dimers and their implications for interactions in the actin filament

Lactone Ring of Pectenotoxins: a Key Factor for their Activity on Cytoskeletal Dynamics

Erythrocyte Tropomodulin Isoforms with and without the N-terminal Actin-binding Domain

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