@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 {2546, title = {Ca2+ binding by domain 2 plays a critical role in the activation and stabilization of gelsolin}, 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: 5Cited Reference Count: 30Nag, Shalini Ma, Qing Wang, Hui Chumnarnsilpa, Sakesit Lee, Wei Lin Larsson, Marten Kannan, Balakrishnan Hernandez-Valladarez, Maria Burtnick, Leslie D. Robinson, Robert C.}, month = {Aug}, pages = {13713-13718}, type = {Article}, abstract = {Gelsolin consists of six homologous domains (G1-G6), each containing a conserved Ca-binding site. Occupation of a subset of these sites enables gelsolin to sever and cap actin filaments in a Ca-dependent manner. Here, we present the structures of Ca-free human gelsolin and of Ca-bound human G1-G3 in a complex with actin. These structures closely resemble those determined previously for equine gelsolin. However, the G2 Ca-binding site is occupied in the human G1-G3/actin structure, whereas it is vacant in the equine version. In-depth comparison of the Ca-free and Ca-activated, actin-bound human gelsolin structures suggests G2 and G6 to be cooperative in binding Ca2+ and responsible for opening the G2-G6 latch to expose the F-actin-binding site on G2. Mutational analysis of the G2 and G6 Ca-binding sites demonstrates their interdependence in maintaining the compact structure in the absence of calcium. Examination of Ca binding by G2 in human G1-G3/actin reveals that the Ca2+ locks the G2-G3 interface. Thermal denaturation studies of G2-G3 indicate that Ca binding stabilizes this fragment, driving it into the active conformation. The G2 Ca-binding site is mutated in gelsolin from familial amyloidosis (Finnish-type) patients. This disease initially proceeds through protease cleavage of G2, ultimately to produce a fragment that forms amyloid fibrils. The data presented here support a mechanism whereby the loss of Ca binding by G2 prolongs the lifetime of partially activated, intermediate conformations in which the protease cleavage site is exposed.}, keywords = {actin, AMYLOIDOGENESIS, biosynthesis, calcium, calcium activated, calcium dependent, FAMILIAL AMYLOIDOSIS, IDENTIFICATION, PLASMA GELSOLIN, PROTEIN, SITE, TERMINAL HALF, TIRF}, isbn = {0027-8424}, url = {://000269078700018}, author = {Nag, S. and Ma, Q. and Wang, H. and Chumnarnsilpa, S. and Lee, W. L. and Larsson, M. and Kannan, B. and Hernandez-Valladarez, 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 {891, title = {Structural basis of actin sequestration by thymosin-beta 4: implications for WH2 proteins}, journal = {Embo Journal}, volume = {23}, number = {18}, year = {2004}, note = {ISI Document Delivery No.: 861IFTimes Cited: 48Cited Reference Count: 51}, month = {Sep}, pages = {3599-3608}, type = {Article}, abstract = {The WH2 (Wiscott - Aldridge syndrome protein homology domain 2) repeat is an actin interacting motif found in monomer sequestering and filament assembly proteins. We have stabilized the prototypical WH2 family member, thymosin-beta4 (Tbeta4), with respect to actin, by creating a hybrid between gelsolin domain 1 and the C-terminal half of Tbeta4 (G1-Tbeta4). This hybrid protein sequesters actin monomers, severs actin filaments and acts as a leaky barbed end cap. Here, we present the structure of the G1-Tbeta4: actin complex at 2Angstrom resolution. The structure reveals that Tbeta4 sequesters by capping both ends of the actin monomer, and that exchange of actin between Tb4 and profilin is mediated by a minor overlap in binding sites. The structure implies that multiple WH2 motif-containing proteins will associate longitudinally with actin filaments. Finally, we discuss the role of the WH2 motif in arp2/3 activation.}, keywords = {actin, ARP2/3 COMPLEX, BETA-THYMOSINS, BINDING-PROTEINS, CRYSTAL-STRUCTURE, DNASE-I, F-ACTIN, MONOMERIC, NEGATIVE COOPERATIVITY, NMR-SPECTROSCOPY, NUCLEAR-MAGNETIC-RESONANCE, protein crystallography, SCAR, VCA, WASp, WH2}, isbn = {0261-4189}, url = {://000224409100003}, author = {Irobi, E. and Aguda, A. H. and Larsson, M. and Guerin, C. and Yin, H. L. and Burtnick, L. D. and Blanchoin, L. 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 {4646, title = {Domain movement in gelsolin: A calcium-activated switch}, journal = {Science}, volume = {286}, number = {5446}, year = {1999}, note = {ISI Document Delivery No.: 261HHTimes Cited: 94Cited Reference Count: 18}, month = {Dec}, pages = {1939-1942}, type = {Article}, abstract = {The actin-binding protein gelsolin is involved in remodeling the actin cytoskeleton during growth-factor signaling, apoptosis, cytokinesis, and cell movement. Calcium-activated gelsolin severs and caps actin filaments, The 3.4 angstrom x-ray structure of the carboxyl-terminal half of gelsolin (G4-G6) in complex with actin reveals the basis for gelsolin activation. Calcium binding induces a conformational rearrangement in which domain G6 is flipped over and translated by about 40 angstroms relative to G4 and G5. The structural reorganization tears apart the continuous beta sheet core of G4 and G6. This exposes the actin-binding site on G4, enabling severing and capping of actin filaments to proceed.}, keywords = {actin, BINDING-SITE, COMPLEX, FILAMENT, IDENTIFICATION, PLASMA GELSOLIN}, isbn = {0036-8075}, url = {://000084003400047}, author = {Robinson, R. C. and Mejillano, M. and Le, V. P. and Burtnick, L. D. and Yin, H. L. and Choe, S.} } @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 {7352, title = {STABILIZATION OF THE STRUCTURE OF HORSE PLASMA VITAMIN-D BINDING-PROTEIN BY DISULFIDE BONDS}, journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire}, volume = {70}, number = {1}, year = {1992}, note = {ISI Document Delivery No.: HG742Times Cited: 1Cited Reference Count: 27}, month = {Jan}, pages = {10-15}, type = {Article}, abstract = {Vitamin D binding protein (DBP) was isolated from horse plasma in a four-step procedure that involved Affi-Gel Blue affinity chromatography, gel filtration, hydroxylapatite chromatography, and anion exchange high-pressure liquid chromatography. The yield of DBP from 80 mL of plasma was 6-7 mg. Horse plasma DBP closely resembles other plasma DBPs, being a tryptophan-free protein of M(r) 53 000. It is able to bind to and block the polymerization of monomeric actin. The secondary structure of DBP was calculated from circular dichroism measurements to be 39\% alpha-helix, 42\% beta-sheet, and 19\% random coil. Circular dichroism and fluorescence studies revealed that the disulfide bonds of DBP contribute substantial structural stabilization to the molecule with respect to thermal denaturation. The thermal stability of DBP can be used to advantage. Incorporation of a brief treatment at 70-degrees-C into the preparative scheme enables omission of one chromatographic step, without detectable alteration of the purified product.}, keywords = {actin, circular dichroism, CIRCULAR-DICHROISM, COMPLEX, denaturation, DISULFIDE BONDS, FLUORESCENCE, GC-GLOBULIN, POLYMERIZATION, RAT, SERUM, thermal, TROPOMYOSIN, VITAMIN-D BINDING PROTEIN}, isbn = {0829-8211}, url = {://A1992HG74200002}, author = {Robinson, R. C. and Burtnick, L. D.} } @article {7110, title = {INTERACTION OF HORSE PLASMA GELSOLIN WITH THE HYDROPHOBIC FLUORESCENT-PROBE 2-(N-METHYLANILINO)NAPHTHALENE-6-SULFONIC ACID}, journal = {Biochemistry International}, volume = {23}, number = {5}, year = {1991}, note = {ISI Document Delivery No.: FR334Times Cited: 2Cited Reference Count: 15}, month = {Mar}, pages = {905-913}, type = {Article}, keywords = {2-AMINONAPHTHALENE-6-SULFONATE, actin, BINDING, Electronic spectra, MOLECULES, PROTEIN}, isbn = {0158-5231}, url = {://A1991FR33400011}, author = {Silva, B. E. R. and Burtnick, L. D. and Turro, N. J.} }