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Nag S, Larsson M, Robinson RC, Burtnick LD. Gelsolin: The tail of a molecular gymnast. Cytoskeleton (Hoboken) 2013; 70:360-84. [DOI: 10.1002/cm.21117] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/24/2013] [Indexed: 12/14/2022]
Affiliation(s)
| | - Mårten Larsson
- Institute of Molecular and Cell Biology, A*STAR; Singapore
| | | | - Leslie D. Burtnick
- Department of Chemistry and Centre for Blood Research; Life Sciences Institute, University of British Columbia; Vancouver; British Columbia; Canada
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Garg R, Peddada N, Sagar A, Nihalani D, Ashish. Visual insight into how low pH alone can induce actin-severing ability in gelsolin under calcium-free conditions. J Biol Chem 2011; 286:20387-97. [PMID: 21498516 PMCID: PMC3121526 DOI: 10.1074/jbc.m111.236943] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 04/07/2011] [Indexed: 01/17/2023] Open
Abstract
Gelsolin is a key actin cytoskeleton-modulating protein primarily regulated by calcium and phosphoinositides. In addition, low pH has also been suggested to activate gelsolin in the absence of Ca(2+) ions, although no structural insight on this pathway is available except for a reported decrement in its diffusion coefficient at low pH. We also observed ~1.6-fold decrease in the molecular mobility of recombinant gelsolin when buffer pH was lowered from 9 to 5. Analysis of the small angle x-ray scattering data collected over the same pH range indicated that the radius of gyration and maximum linear dimension of gelsolin molecules increased from 30.3 to 34.1 Å and from 100 to 125 Å, respectively. Models generated for each dataset indicated that similar to the Ca(2+)-induced process, low pH also promotes unwinding of this six-domain protein but only partially. It appeared that pH is able to induce extension of the G1 domain from the rest of the five domains, whereas the Ca(2+)-sensitive latch between G2 and G6 domains remains closed. Interestingly, increasing the free Ca(2+) level to merely ~40 nM, the partially open pH 5 shape "sprung open" to a shape seen earlier for this protein at pH 8 and 1 mm free Ca(2+). Also, pH alone could induce a shape where the g3-g4 linker of gelsolin was open when we truncated the C-tail latch from this protein. Our results provide insight into how under physiological conditions, a drop in pH can fully activate the F-actin-severing shape of gelsolin with micromolar levels of Ca(2+) available.
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Affiliation(s)
- Renu Garg
- the Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, 160036, India
| | - Nagesh Peddada
- the Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, 160036, India
| | - Amin Sagar
- the Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, 160036, India
| | - Deepak Nihalani
- From the Renal, Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania 19104 and
| | - Ashish
- the Institute of Microbial Technology, Council of Scientific and Industrial Research (CSIR), Chandigarh, 160036, India
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Hayes MJ, Shao DM, Grieve A, Levine T, Bailly M, Moss SE. Annexin A2 at the interface between F-actin and membranes enriched in phosphatidylinositol 4,5,-bisphosphate. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:1086-95. [PMID: 19022301 DOI: 10.1016/j.bbamcr.2008.10.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 10/03/2008] [Accepted: 10/15/2008] [Indexed: 11/16/2022]
Abstract
Vesicle rocketing has been used as a model system for understanding the dynamics of the membrane-associated F-actin cytoskeleton, but in many experimental systems is induced by persistent, non-physiological stimuli. Localised changes in the concentration of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in membranes stimulate the recruitment of actin-remodelling proteins to their sites of action, regulate their activity and favour vesicle rocketing. The calcium and anionic phospholipid-binding protein annexin A2 is necessary for macropinocytic rocketing and has been shown to bind both PI(4,5)P2 and the barbed-ends of F-actin filaments. Here we show that annexin A2 localises to the comet tails which form constitutively in fibroblasts from patients with Lowe Syndrome. These fibroblasts are deficient in OCRL1, a phosphatidylinositol polyphosphate 5-phosphatase with specificity for PI(4,5)P2. We show that upon depletion of annexin A2 from these cells vesicle rocketing is reduced, and that this is also dependent upon PI(4,5)P2 formation. Annexin A2 co-localised with comet-tails induced by pervanadate and hyperosmotic shock in a basophilic cell line, and in an epithelial cell line upon activation of PKC. In vitro annexin A2 promoted comet formation in a bead-rocketing assay and was sufficient to link F-actin filaments to PI(4,5)P2 containing vesicles. These observations are consistent with a role for annexin A2 as an actin nucleator on PI(4,5)P2-enriched membranes.
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Affiliation(s)
- Matthew J Hayes
- Division of Cell Biology, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK.
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Ferjani I, Fattoum A, Maciver SK, Manai M, Benyamin Y, Roustan C. Two distinct sites of interaction form the calponin: gelsolin complex and two calcium switches control its activity. BIOCHIMICA ET BIOPHYSICA ACTA 2007; 1774:952-8. [PMID: 17556051 DOI: 10.1016/j.bbapap.2007.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 04/25/2007] [Accepted: 04/27/2007] [Indexed: 10/23/2022]
Abstract
Gelsolin and calponin are well characterized actin-binding proteins that form a tight gelsolin:calponin complex (GCC). We show here that the GCC is formed through two distinct interfaces. One of these is formed between 144-182 of calponin and 25-150 of gelsolin (G1). The second is a calcium-sensitive site centred on calponin's CH domain, and the C-terminal half of gelsolin (G4-6). The behaviour of this second interface is dependent on the presence of calcium and so it is possible that potential GCC-binding partners may be selected by calcium availability. Actin is one such GCC-binding partner and we show that a larger complex is formed with monomeric actin in calcium. The stoichiometry of this complex is determined to be 1 gelsolin/1 calponin/2 G-actins (GCA(2)). Both actin monomers bind the GCC through gelsolin. Both calponin and gelsolin are reported to play signaling roles in addition to their better-characterized actin-binding properties and it is possible that the GCC regulates both of these functions.
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Affiliation(s)
- Imen Ferjani
- DIMNP, University of Montpellier 2 and 1, CNRS Montpellier, Place E, Bataillon, CC107, 34095 Montpellier Cedex 5, France
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Paine MS, Perryman PB, Yang L, Yin HL, Krueger JK. Global structure changes associated with Ca2+ activation of full-length human plasma gelsolin. J Biol Chem 2007; 282:25884-92. [PMID: 17604278 DOI: 10.1074/jbc.m702446200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gelsolin regulates the dynamic assembly and disassembly of the actin-based cytoskeleton in non-muscle cells and clears the circulation of filaments released following cell death. Gelsolin is a six-domain (G1-G6) protein activated by calcium via a multi-step process that involves unfolding from a compact form to a more open form in which the three actin-binding sites (on the G1, G2, and G4 subdomains) become exposed. To follow the global structural changes that accompany calcium activation of gelsolin, small-angle x-ray scattering (SAXS) data were collected for full-length human plasma gelsolin at nanomolar to millimolar concentrations of free Ca2+. Analysis of these data showed that, upon increasing free Ca2+ levels, the radius of gyration (Rg) increased nearly 12 A, from 31.1+/-0.3 to 43+/-2 A, and the maximum linear dimension (Dmax) of the gelsolin molecule increased 55 A, from 100 to 155A. Structural reconstruction of gelsolin from these data provided a striking visual tracking of the gradual Ca2+-induced opening of the gelsolin molecule and highlighted the critical role played by the flexible linkers between homologous domains. The tightly packed architecture of calcium-free gelsolin, seen from both SAXS and x-ray crystallographic models, is already partially opened up in as low as 0.5 nM Ca2+. Our data confirm that, although the molecule springs open from 0 to 1 microM free Ca2+, even higher calcium concentrations help to stabilize a more open structure, with increases in Rg and Dmax of approximately 2 and approximately 15 A, respectively. At these higher calcium levels, the SAXS-based models provide a molecular shape that is compatible with that of the crystal structures solved for Ca2+/gelsolin C-terminal and N-terminal halves+/-monomeric G-actin. Placement of these crystal structures within the boundaries of the SAXS-based model suggests a movement of the G1/G2 subunits that would be required upon binding to actin.
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Roustan C, Ferjani I, Maciver SK, Fattoum A, Rebière B, Benyamin Y. Calcium-induced conformational changes in the amino-terminal half of gelsolin. FEBS Lett 2007; 581:681-6. [PMID: 17258204 DOI: 10.1016/j.febslet.2007.01.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Revised: 12/05/2006] [Accepted: 01/15/2007] [Indexed: 11/27/2022]
Abstract
Gelsolin is an actin-binding protein that is regulated by the occupancy of multiple calcium-binding sites. We have studied calcium induced conformational changes in the G1-2 and G1-3 sub-domains, and report the binding affinities for the three type II sites. A new probe for G3 has been produced and a K(d) of 5 microM has been measured for calcium in the context of G1-3. The two halves of gelsolin, G1-3 and G4-6 bind weakly with or without calcium, suggesting that once separated by apoptotic proteolysis, G1-3 and G4-6 remain apart allowing G1-3 to sever actin in a calcium free manner.
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Affiliation(s)
- Claude Roustan
- UMR 5539 (CNRS) Laboratoire de motilité cellulaire (Ecole Pratique des Hautes Etudes), Université de Montpellier 2, Place E. Bataillon, CC107, 34095 Montpellier Cedex 5, France
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Nichols CE, Johnson C, Lockyer M, Charles IG, Lamb HK, Hawkins AR, Stammers DK. Structural characterization of Salmonella typhimurium YeaZ, an M22 O-sialoglycoprotein endopeptidase homolog. Proteins 2006; 64:111-23. [PMID: 16617437 DOI: 10.1002/prot.20982] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The Salmonella typhimurium "yeaZ" gene (StyeaZ) encodes an essential protein of unknown function (StYeaZ), which has previously been annotated as a putative homolog of the Pasteurella haemolytica M22 O-sialoglycoprotein endopeptidase Gcp. YeaZ has also recently been reported as the first example of an RPF from a gram-negative bacterial species. To further characterize the properties of StYeaZ and the widely occurring MK-M22 family, we describe the purification, biochemical analysis, crystallization, and structure determination of StYeaZ. The crystal structure of StYeaZ reveals a classic two-lobed actin-like fold with structural features consistent with nucleotide binding. However, microcalorimetry experiments indicated that StYeaZ neither binds polyphosphates nor a wide range of nucleotides. Additionally, biochemical assays show that YeaZ is not an active O-sialoglycoprotein endopeptidase, consistent with the lack of the critical zinc binding motif. We present a detailed comparison of YeaZ with available structural homologs, the first reported structural analysis of an MK-M22 family member. The analysis indicates that StYeaZ has an unusual orientation of the A and B lobes which may require substantial relative movement or interaction with a partner protein in order to bind ligands. Comparison of the fold of YeaZ with that of a known RPF domain from a gram-positive species shows significant structural differences and therefore potentially distinctive RPF mechanisms for these two bacterial classes.
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Affiliation(s)
- C E Nichols
- Division of Structural Biology, The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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Apostolova MD, Christova T, Templeton DM. Involvement of gelsolin in cadmium-induced disruption of the mesangial cell cytoskeleton. Toxicol Sci 2005; 89:465-74. [PMID: 16280379 DOI: 10.1093/toxsci/kfj035] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Cadmium (Cd2+) is known to cause a selective disruption of the filamentous actin cytoskeleton in the smooth muscle-like renal mesangial cell. We examined the effect of Cd2+ on the distribution of the actin-severing protein, gelsolin. Over 8 h, CdCl2 (10 microM) caused a progressive shift of gelsolin from a diffuse perinuclear and cytoplasmic distribution to a pattern decorating F-actin filaments. Over this time filaments were decreased in number in many cells, and membrane ruffling was initiated. Western blotting and 125I-F-actin gel overlays demonstrated an increase in actin-binding gelsolin activity in the cytoskeletal fraction of cell extracts following Cd2+ treatment. In in vitro polymerization assays, gelsolin acted as a nucleating factor and increased the rate of polymerization. Cytosolic extracts also increased the polymerization rate. Addition of Cd2+ together with gelsolin further increased the rate of polymerization. Gelsolin enhanced depolymerization of purified actin, and Cd2+ partially suppressed this effect. However, cytoskeletal extracts from Cd2+-treated cells also markedly increased depolymerization, suggesting further that Cd2+ may activate cellular component(s) such as gelsolin for actin binding. We conclude that a major effect of Cd2+ on the mesangial cell cytoskeleton is manifest through activating the association of gelsolin with actin, with gelsolin's severing properties predominating under conditions found in Cd2+-treated cells.
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Affiliation(s)
- Margarita D Apostolova
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, M5S 1A8, Canada
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McGough AM, Staiger CJ, Min JK, Simonetti KD. The gelsolin family of actin regulatory proteins: modular structures, versatile functions. FEBS Lett 2003; 552:75-81. [PMID: 14527663 DOI: 10.1016/s0014-5793(03)00932-3] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This issue of FEBS Letters includes two manuscripts describing structural studies of gelsolin, the best-characterized member of a superfamily of actin binding proteins that sever, cap, and in some cases nucleate and bundle actin filaments. The manuscripts by Narayan et al. and Irobi et al. provide snapshots of gelsolin domains activated by calcium and in complex with the actin monomer, revealing new insights into the remarkable actin regulatory activities of this versatile protein. These studies build upon nearly a quarter of a century of research on gelsolin's effects on actin dynamics and its role in normal and diseased cells. In the following minireview, we summarize the structural studies that have provided insights into gelsolin's severing and capping activities and look to the future of work on this remarkable molecule.
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Affiliation(s)
- Amy M McGough
- Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47907-1392, USA.
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Lagarrigue E, Ternent D, Maciver SK, Fattoum A, Benyamin Y, Roustan C. The activation of gelsolin by low pH. ACTA ACUST UNITED AC 2003; 270:4105-12. [PMID: 14519122 DOI: 10.1046/j.1432-1033.2003.03803.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gelsolin is a multidomain and multifunction protein that nucleates the assembly of filaments and severs them. The activation of gelsolin by calcium is a multistep process involving many calcium binding sites that act to unfold the molecule from a tight structure to a more loose form in which three actin-binding sites become exposed. Low pH is also known to activate gelsolin, in the absence of calcium and this too results in an unfolding of the molecule. Less is known how pH-activation occurs but we show that there are significant differences in the mechanisms that lead to activation. Crucially, while it is known that the bonds between G2 and G6 are broken by co-operative occupancy of calcium binding sites in both domains [Lagarrique, E., Maciver, S. K., Fattoum, A., Benyamin, Y. & Roustan, C. (2003) Eur. J. Biochem. 270, 2236-2243.], pH values that activate gelsolin do not result in a weakening of the G2-G6 bonds. We report the existence of pH-dependent conformational changes within G2 and in G4-6 that differ from those induced by calcium, and that low pH overrides the requirement for calcium for actin-binding within G4-6 to a modest extent so that a Kd of 1 micro m is measured, compared to 30-40 nm in the presence of calcium. Whereas the pH-dependent conformational change in G2 is possibly different from the change induced by calcium, the changes measured in G4-6 appear to be similar in both calcium and low pH.
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Affiliation(s)
- Emeline Lagarrigue
- UMR 5539 (CNRS) Laboratoire de motilité cellulaire (Ecole Pratique des Hautes Etudes), Université de Montpellier 2, Montpellier Cedex 5, France
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