@article {12934, title = {The expanding superfamily of gelsolin homology domain proteins}, journal = {Cytoskeleton}, volume = {70}, year = {2013}, month = {11/2013}, pages = {775-795}, type = {research}, chapter = {775}, abstract = {

The gelsolin homology (GH) domain has been found
to date exclusively in actin-binding proteins. In
humans, three copies of the domain are present in
CapG, five copies in supervillin, and six copies each in
adseverin, gelsolin, flightless I and the villins: villin,
advillin and villin-like protein. Caenorhabditis elegans
contains a four-GH-domain protein, GSNL-1. These
architectures are predicted to have arisen from gene
triplication followed by gene duplication to result in
the six-domain protein. The subsequent loss of one,
two or three domains produced the five-, four-, and
three-domain proteins, respectively. Here we conducted
BLAST and hidden Markov based searches of UniProt
and NCBI databases to identify novel gelsolin domain
containing proteins. The variety in architectures suggests
that the GH domain has been tested in many
molecular constructions during evolution. Of particular
note is flightless-like I protein (FLIIL1) from Entamoeba
histolytica, which combines a leucine rich
repeats (LRR) domain, seven GH domains, and a headpiece
domain, thus combining many of the features of
flightless I with those of villin or supervillin. As such,
the GH domain superfamily appears to have developed
along complex routes. The distribution of these proteins
was analyzed in the 343 completely sequenced
genomes, mapped onto the tree of life, and phylogenetic
trees of the proteins were constructed to gain
insight into their evolution.

}, keywords = {actin, flightless, gelsolin, supervillin, VILLIN}, doi = {10.1002/cm.21149}, author = {Ghoshdastider, U. and Popp, D. and Burtnick, L. D. and Robinson, R. C.} } @article {2395, title = {The crystal structure of the C-terminus of adseverin reveals the actin-binding interface}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {106}, number = {33}, year = {2009}, note = {ISI Document Delivery No.: 484WETimes Cited: 0Cited Reference Count: 21Chumnarnsilpa, Sakesit Lee, Wei Lin Nag, Shalini Kannan, Balakrishnan Larsson, Marten Burtnick, Leslie D. Robinson, Robert C.}, month = {Aug}, pages = {13719-13724}, type = {Article}, abstract = {Adseverin is a member of the calcium-regulated gelsolin superfamily of actin severing and capping proteins. Adseverin comprises 6 homologous domains (A1-A6), which share 60\% identity with the 6 domains from gelsolin (G1-G6). Adseverin is truncated in comparison to gelsolin, lacking the C-terminal extension that masks the F-actin binding site in calcium-free gelsolin. Biochemical assays have indicated differences in the interaction of the C-terminal halves of adseverin and gelsolin with actin. Gelsolin contacts actin through a major site on G4 and a minor site on G6, whereas adseverin uses a site on A5. Here, we present the X-ray structure of the activated C-terminal half of adseverin (A4-A6). This structure is highly similar to that of the activated form of the C-terminal half of gelsolin (G4-G6), both in arrangement of domains and in the 3 bound calcium ions. Comparative analysis of the actin-binding surfaces observed in the G4-G6/actin structure suggests that adseverin in this conformation will also be able to interact with actin through A4 and A6, whereas the A5 surface is obscured. A single residue mutation in A4-A6 located at the predicted A4/actin interface completely abrogates actin sequestration. A model of calcium-free adseverin, constructed from the structure of gelsolin, predicts that in the absence of a gelsolin-like C-terminal extension the interaction between A2 and A6 provides the steric inhibition to prevent interaction with F-actin. We propose that calcium binding to the N terminus of adseverin dominates the activation process to expose the F-actin binding site on A2.}, keywords = {74-KDA PROTEIN, ACTIVATION, calcium activated, EXOCYTOSIS, gelsolin, HALF, LOCALIZATION, SCINDERIN, SITE, TIRF}, isbn = {0027-8424}, url = {://000269078700019}, author = {Chumnarnsilpa, S. and Lee, W. L. and Nag, S. and Kannan, B. and Larsson, M. and Burtnick, L. D. and Robinson, R. C.} } @article {1368, title = {Calcium ion exchange in crystalline gelsolin}, journal = {Journal of Molecular Biology}, volume = {357}, number = {3}, year = {2006}, note = {ISI Document Delivery No.: 030IYTimes Cited: 6Cited Reference Count: 24}, month = {Mar}, pages = {773-782}, type = {Article}, abstract = {Gelsolin is a calcium and pH-sensitive modulator of actin filament length. Here, we use X-ray crystallography to examine the extraction and exchange of calcium ions from their binding sites in different crystalline forms of the activated N and C-terminal halves of gelsolin, G1-G3 and G4-G6, respectively. We demonstrate that the combination of calcium and low pH activating conditions do not induce conformational changes in G4-G6 beyond those elicited by calcium alone. EGTA is able to remove calcium ions bound to the type I and type II metal ion-binding sites in G4-G6. Constrained by crystal contacts and stabilized by interdomain interaction surfaces, the gross structure of calcium-depleted G4-G6 remains that of the activated form. However, high-resolution details of changes in the ion-binding sites may represent the initial steps toward restoration of the arrangement of domains found in the calcium-free inactive form of gelsolin in solution. Furthermore, bathing crystals with the trivalent calcium ion mimic, Tb3+, results in anomalous scattering data that permit unequivocal localization of terbium ions in each of the proposed type I and type II ion-binding sites of both halves of gelsolin. In contrast to predictions based on solution studies, we find that no calcium ion is immune to exchange. (c) 2006 Elsevier Ltd. All rights reserved.}, keywords = {actin, ACTIN MONOMER, ACTIVATION, apoptosis, BINDING-SITE, C-TERMINAL HALF, calcium activation, COMPLEX, CONFORMATIONAL CHANGE, DOMAINS, ELECTRON-DENSITY MAPS, gelsolin, IDENTIFICATION, MECHANISMS, protein crystallography}, isbn = {0022-2836}, url = {://000236629300008}, author = {Chumnarnsilpa, S. and Loonchanta, A. and Xue, B. and Choe, H. and Urosev, D. and Wang, H. and Lindberg, U. and Burtnick, L. D. and Robinson, R. C.} } @article {1612, title = {The structure of gelsolin bound to ATP}, journal = {Journal of Molecular Biology}, volume = {357}, number = {3}, year = {2006}, note = {ISI Document Delivery No.: 030IYTimes Cited: 7Cited Reference Count: 28}, month = {Mar}, pages = {765-772}, type = {Article}, abstract = {Calcium activation of the actin-modifying properties of gelsolin is sensitive to ATP. Here, we show that soaking calcium-free gelsolin crystals in ATP-containing media results in ATP occupying a site that spans the two pseudosymmetrical halves of the protein. ATP binding involves numerous polar and hydrophobic contacts and is identical for the two copies of gelsolin related by non-crystallographic symmetry within the crystal. The gamma-phosphate of ATP participates in several charge-charge interactions consistent with the preference of gelsolin for ATP, as a binding partner, over ADP. In addition, disruption of the ATP-binding site through Ca2+ activation of gelsolin reveals why ATP binds more tightly to the inactive molecule, and suggests how the binding of ATP may modulate the sensitivity of gelsolin to calcium ions. Similarities between the ATP and PIP2 interactions with the C-terminal half of gelsolin are evident from their overlapping binding sites and in that both molecules bind more tightly in the absence of calcium ions. We propose a model for how PIP2 may bind to calcium-free gelsolin based on the ATP-binding site. (c) 2006 Elsevier Ltd. All rights reserved.}, keywords = {5-BISPHOSPHATE, actin, ATP, BINDING-SITE, calcium, CRYSTAL-STRUCTURE, DOMAIN, gelsolin, HUMAN-PLASMA GELSOLIN, IDENTIFICATION, PHOSPHATIDYLINOSITOL 4, PIP2, PROTEIN, TERMINAL HALF}, isbn = {0022-2836}, url = {://000236629300007}, author = {Urosev, D. and Ma, Q. and Tan, A. L. C. and Robinson, R. C. and Burtnick, L. D.} } @article {1053, title = {The state of the filament}, journal = {Embo Reports}, volume = {6}, number = {3}, year = {2005}, note = {ISI Document Delivery No.: 901QMTimes Cited: 22Cited Reference Count: 30}, month = {Mar}, pages = {220-226}, type = {Review}, abstract = {Movement is a defining characteristic of life. Macroscopic motion is driven by the dynamic interactions of myosin with actin filaments in muscle. Directed polymerization of actin behind the advancing membrane of a eukaryotic cell generates microscopic movement. Despite the fundamental importance of actin in these processes, the structure of the actin filament remains unknown. The Holmes model of the actin filament was published 15 years ago, and although it has been widely accepted, no high-resolution structural data have yet confirmed its veracity. Here, we review the implications of recently determined structures of F-actin-binding proteins for the structure of the actin filament and suggest a series of in silico tests for actin-filament models. We also review the significance of these structures for the arp2/3-mediated branched filament.}, keywords = {actin filament, ACTIN-FILAMENT, ACTIVATION, ALDRICH-SYNDROME PROTEIN, arp2/3, ARP2/3 COMPLEX, BETA-ACTIN, CRYSTAL-STRUCTURE, DOMAIN, gelsolin, STRUCTURAL BASIS, STRUCTURE, WASp, WH2}, isbn = {1469-221X}, url = {://000227297000009}, author = {Aguda, A. H. and Burtnick, L. D. and Robinson, R. C.} } @article {813, title = {Structure of the N-terminal half of gelsolin bound to actin: roles in severing, apoptosis and FAF}, journal = {Embo Journal}, volume = {23}, number = {14}, year = {2004}, note = {ISI Document Delivery No.: 847NBTimes Cited: 41Cited Reference Count: 59}, month = {Jul}, pages = {2713-2722}, type = {Article}, abstract = {The actin filament-severing functionality of gelsolin resides in its N-terminal three domains (G1 - G3). We have determined the structure of this fragment in complex with an actin monomer. The structure reveals the dramatic domain rearrangements that activate G1 - G3, which include the replacement of interdomain interactions observed in the inactive, calcium-free protein by new contacts to actin, and by a novel G2 - G3 interface. Together, these conformational changes are critical for actin filament severing, and we suggest that their absence leads to the disease Finnish-type familial amyloidosis. Furthermore, we propose that association with actin drives the calcium-independent activation of isolated G1 G3 during apoptosis, and that a similar mechanism operates to activate native gelsolin at micromolar levels of calcium. This is the first structure of a filament-binding protein bound to actin and it sets stringent, high-resolution limitations on the arrangement of actin protomers within the filament.}, keywords = {5-BISPHOSPHATE, actin, AMYLOIDOSIS-FINNISH TYPE, apoptosis, BINDING-SITE, CA2+ REGULATION, calcium, CRYSTAL-STRUCTURE, crystallographic structure, F-ACTIN, FAMILIAL AMYLOIDOSIS, FILAMENT BARBED ENDS, gelsolin, PHOSPHATIDYLINOSITOL 4, PLASMA GELSOLIN, X-RAY}, isbn = {0261-4189}, url = {://000223398800002}, author = {Burtnick, L. D. and Urosev, D. and Irobi, E. and Narayan, K. and Robinson, R. C.} } @article {697, title = {Activation in isolation: exposure of the actin-binding site in the C-terminal half of gelsolin does not require actin}, journal = {Febs Letters}, volume = {552}, number = {2-3}, year = {2003}, note = {ISI Document Delivery No.: 726DKTimes Cited: 15Cited Reference Count: 23}, month = {Sep}, pages = {82-85}, type = {Article}, abstract = {Gelsolin requires activation to carry out its severing and capping activities on F-actin. Here, we present the structure of the isolated C-terminal half of gelsolin (G4-G6) at 2.0 resolution in the presence of Ca2+ ions. This structure completes a triptych of the states of activation of G4-G6 that illuminates its role in the function of gelsolin. Activated G4-G6 displays an open conformation, with the actin-binding site on G4 fully exposed and all three type-2 Ca2+ sites occupied. Neither actin nor the type-1 Ca2+, which normally is sandwiched between actin and G4, is required to achieve this conformation. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.}, keywords = {actin, calcium-activation, COMPLEX, DOMAINS, F-ACTIN, gelsolin, PLASMA GELSOLIN, REGULATORY PROTEIN, TRANSFORMATION}, isbn = {0014-5793}, url = {://000185583000002}, author = {Narayan, K. and Chumnarnsilpa, S. and Choe, H. and Irobi, E. and Urosev, D. and Lindberg, U. and Schutt, C. E. and Burtnick, L. D. and Robinson, R. C.} } @article {643, title = {From the first to the second domain of gelsolin: a common path on the surface of actin?}, journal = {Febs Letters}, volume = {552}, number = {2-3}, year = {2003}, note = {ISI Document Delivery No.: 726DKTimes Cited: 22Cited Reference Count: 29}, month = {Sep}, pages = {86-90}, type = {Article}, abstract = {We present the 2.6. resolution crystal structure of a complex formed between G-actin and gelsolin fragment Met25-GIn160 (G1+). The structure differs from those of other gelsolin domain 1 (G1) complexes in that an additional six amino acid residues from the crucial linker region into gelsolin domain 2 (G2) are visible and are attached securely to the surface of actin. The linker segment extends away from G1 up the face of actin in a direction that infers G2 will bind along the same long-pitch helical strand as the actin bound to G1. This is consistent with a mechanism whereby G2 attaches gelsolin to the side of a filament and then directs G1 toward a position where it would disrupt actin-actin contacts. Alignment of the sequence of the structurally important residues within the G1-G2 linker with those of WH2 (WASp homology domain 2) domain protein family members (e.g. WASp (Wiscott-Aldridge syndrome protein) and thymosin beta4) suggests that the opposing activities of filament assembly and disassembly may exploit a common patch on the surface of actin. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.}, keywords = {actin, BINDING, calcium, COMPLEX, crystal structure, DIFFRACTION DATA, F-ACTIN, FILAMENT, gelsolin, IDENTIFICATION, MODEL, MOTILITY, NUCLEATION, WH2 domain}, isbn = {0014-5793}, url = {://000185583000003}, author = {Irobi, E. and Burtnick, L. D. and Urosev, D. and Narayan, K. and Robinson, R. C.} } @article {348, title = {The calcium activation of gelsolin: Insights from the 3 angstrom structure of the G4-G6/actin complex}, journal = {Journal of Molecular Biology}, volume = {324}, number = {4}, year = {2002}, note = {ISI Document Delivery No.: 625PRTimes Cited: 48Cited Reference Count: 32}, month = {Dec}, pages = {691-702}, type = {Article}, abstract = {Gelsolin participates in the reorganization of the actin cytoskeleton that is required during such phenomena as cell movement, cytokinesis, and apoptosis. It consists of six structurally similar domains, G1-G6, which are arranged at resting intracellular levels of calcium ion so as to obscure the three actin-binding surfaces. Elevation of Ca2+ concentrations releases latches within the constrained structure and produces large shifts in the relative positioning of the domains, permitting gelsolin to bind to and sever actin filaments. How Ca2+ is able to activate gelsolin has been a major question concerning the function of this protein. We present the improved structure of the C-terminal half of gelsolin bound to monomeric actin at 3.0 Angstrom resolution. Two classes of Ca2+-binding site are evident on gelsolin: type 1 sites share coordination of Ca2+ with actin, while type 2 sites are wholly contained within gelsolin. This structure of the complex reveals the locations of two novel metal ion-binding sites in domains G5 and G6, respectively. We identify both as type 2 sites. The absolute conservation of the type 2 calcium-ligating residues across the six,domains of gelsolin suggests that this site exists in each of the domains. In total, gelsolin has the potential to bind eight calcium ions, two type 1 and six type 2. The function of the type 2 sites is to facilitate structural rearrangements within gelsolin as part of the activation and actin-binding and severing processes. We propose the novel type 2 site in G6 to be the critical site that initiates overall activation of gelsolin by releasing the tail latch that locks calcium-free gelsolin in a conformation unable to bind actin. (C) 2002 Elsevier Science Ltd. All rights reserved.}, keywords = {actin, ACTIVATION, ACTOPHORIN, BINDING DOMAIN, CA2+, calcium, CAPPING PROTEIN, F-ACTIN, FAMILIAL AMYLOIDOSIS, FINNISH TYPE, gelsolin, IDENTIFICATION, MECHANISM, PLASMA GELSOLIN, REGULATION, severing}, isbn = {0022-2836}, url = {://000179825300011}, author = {Choe, H. and Burtnick, L. D. and Mejillano, M. and Yin, H. L. and Robinson, R. C. and Choe, S.} } @article {4312, title = {Equus caballus gelsolin - cDNA sequence and protein structural implications}, journal = {European Journal of Biochemistry}, volume = {251}, number = {3}, year = {1998}, note = {ISI Document Delivery No.: YV719Times Cited: 4Cited Reference Count: 48}, month = {Feb}, pages = {613-621}, type = {Article}, abstract = {We have generated and characterized the cDNA from equine smooth muscle that Encodes gelsolin, an actin-modulating protein. Overlapping cDNA clones synthesized by the reverse transcriptaseoplymerase chain reaction and clones isolated from a horse genomic library provided the complete primary structure for the intracellular isoform of gelsolin, while cDNA complemented with protein sequence data produced the full-length primary transcript of the gelsolin isoform found circulating in equine plasma. The deduced amino acid sequences of the intracellular and secreted versions of equine gelsolin infer polypeptides of 731 and 755 residues with apparent molecular masses of 80.7 kDa and 83.2 kDa, respectively. Multiple sequence alignment analysis of equine, human, porcine, and murine orthologs of gelsolin demonstrates prominent similarities among all of these proteins, with the horse and human molecules exhibiting the largest degree of likeness with respect to polypeptide length and overall sequence composition. Both horse and human plasma gelsolins are comprised of 755 amino acids with 94\% of the residues identical, while the degree of sequence identity in the shorter (731 residues) cytoplasmic gelsolins is 95 \%. Analysis of the sequences and structures of the six related domains that comprise gelsolin emphasizes the strong correlation that exists between primary structural conservation among mammalian gelsolins and maintenance of the three-dimensional domain fold characteristic of members of this protein family.}, keywords = {actin-binding protein, ACTIN-SEVERING PROTEINS, amino acid sequence, AMPLIFICATION, BINDING DOMAIN, cDNA sequence, CLONING, CYTOPLASMIC FORMS, DNA, END, extraction, gelsolin, HORSE PLASMA GELSOLIN, MUSCLE, protein structure}, isbn = {0014-2956}, url = {://000071855900009}, author = {Koepf, E. K. and Hewitt, J. and Vo, H. and MacGillivray, R. T. A. and Burtnick, L. D.} } @article {3720, title = {Multiple pathways for denaturation of horse plasma gelsolin}, journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire}, volume = {74}, number = {1}, year = {1996}, note = {ISI Document Delivery No.: UE605Times Cited: 1Cited Reference Count: 38}, pages = {101-107}, type = {Article}, abstract = {Gelsolin purified from horse plasma carries a surface charge distribution that greatly influences how the protein unfolds, aggregates, or precipitates as a function of temperature or concentration of chemical denaturant. Modification of gelsolin with fluorescein isothiocyanate replaces positive charges on amine groups with bulky, negatively charged fluorescein moieties. This postpones thermally induced precipitation by about 10 degrees C [Koepf, E.K., and Burtnick, L.D. 1993. Eur. J. Biochem. 212: 713-718]. Interaction with cations such as Ca2+ or guanidinium(+) also alters the surface charge on gelsolin. This affects the structure of the protein in solution, modifies the pathway for unfolding, and moderates the onset of precipitation induced by chemical denaturants or heat. Denaturation of gelsolin is not interpretable in terms of a simple two-state cooperative mechanism. The pathway to a denatured state and intermediate structures present along the way depend upon the agent used to unfold the protein.}, keywords = {ACTIN-BINDING-SITES, calcium, chemical, circular dichroism, denaturation, FLUORESCEIN ISOTHIOCYANATE, gelsolin, PROTEIN, thermal}, isbn = {0829-8211}, url = {://A1996UE60500011}, author = {Koepf, E. K. and Burtnick, L. D.} } @article {7284, title = {INTERACTION OF PLASMA GELSOLIN WITH TROPOMYOSIN}, journal = {Febs Letters}, volume = {309}, number = {1}, year = {1992}, note = {ISI Document Delivery No.: JL068Times Cited: 20Cited Reference Count: 17}, month = {Aug}, pages = {56-58}, type = {Article}, abstract = {Horse plasma gelsolin labelled with benzophenone-4-isothiocyanate can be photochemically cross-linked to rabbit cardiac tropomyosin. The cross-linking proceeds with greater efficiency in calcium-containing buffers. Further evidence for interaction between these proteins is provided by retention of fluorescently labelled gelsolin on tropomyosin-agarose affinity columns and by the ability of tropomyosin to cause an increase in the fluorescence intensity of gelsolin labelled with fluorescein-5-isothiocyanate. Both of these effects require the presence of calcium ions.}, keywords = {actin, FILAMENTS, gelsolin, MUSCLE, PROTEIN, TROPOMYOSIN}, isbn = {0014-5793}, url = {://A1992JL06800013}, author = {Koepf, E. K. and Burtnick, L. D.} } @article {7358, title = {MONOMER AND EXCIMER FLUORESCENCE OF HORSE PLASMA GELSOLIN LABELED WITH N-(1-PYRENYL)IODOACETAMIDE}, journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire}, volume = {70}, number = {7}, year = {1992}, note = {ISI Document Delivery No.: JP667Times Cited: 3Cited Reference Count: 27}, month = {Jul}, pages = {573-578}, type = {Article}, abstract = {Horse plasma gelsolin was labelled with the sulfhydryl-specific fluorescent reagent N-(1-pyrenyl)iodoacetamide. The level of incorporation of probe was 1.6 +/- 0.3 mol pyrene/mol gelsolin. The circular dichroism spectrum of pyrenyl-gelsolin and its ability to interact with muscle actin were not different from that found for unmodified gelsolin. The emission from pyrenyl-gelsolin was dominated by a broad emission band centred near 483 nm, characteristic of the presence of pyrene excimers. Analysis of excitation spectra for the monomer and excimer-type fluorescence suggested that ground-state interactions may occur between adjacent pyrenes in the gelsolin structure. In the case either of excimer formation or of ground-state pyrene-pyrene interactions in doubly labelled gelsolin molecules, the modified Cys residues must be in close proximity in the folded protein structure. Thermal denaturation of gelsolin could be monitored by observing the decrease in excimer emission that accompanied heating and unfolding of the tertiary structure. While heat treatment alone did not eliminate excimer fluorescence, digestion of gelsolin with chymotrypsin completely abolished such emission. Also, pyrenyl-gelsolin prepared and studied in 6 M guanidine-HCl exhibited fluorescence characteristic of pyrene monomers exclusively.}, keywords = {ACTIN-FILAMENTS, BINDING, CIRCULAR-DICHROISM, denaturation, FLUORESCENCE LIFETIME, gelsolin, POLYMERIZATION, PROBE, PROTEIN, PYRENE EXCIMER FLUORESCENCE, PYRENE-ACTIN, STATE, thermal, TROPOMYOSIN}, isbn = {0829-8211}, url = {://A1992JP66700008}, author = {Silva, B. E. R. and Koepf, E. K. and Burtnick, L. D. and Turro, N. J.} }