scholarly journals Gelsolin variant (Asn-187) in familial amyloidosis, Finnish type

1990 ◽  
Vol 272 (3) ◽  
pp. 827-830 ◽  
Author(s):  
J Ghiso ◽  
M Haltia ◽  
F Prelli ◽  
J Novello ◽  
B Frangione
Keyword(s):  
Amyloid Fibrils ◽  
Corneal Dystrophy ◽  
Binding Activity ◽  
Actin Binding ◽  
Cranial Neuropathy ◽  
Protein Subunit ◽  
Plasma Gelsolin ◽  
Sequence Identity ◽  
Finnish Type ◽  
Repetitive Motif

Familial amyloidosis, Finnish type (FAF), is an inherited form of systemic amyloidosis clinically characterized by cranial neuropathy and lattice corneal dystrophy. We have demonstrated that the protein subunit isolated from amyloid fibrils shows considerable sequence identity with gelsolin, an actin-binding protein. We have purified the amyloid subunit from a second case and further analysed different fractions from the previous one. Sequence analysis shows that, in both cases, the amyloid subunit starts at position 173 of the mature molecule; it has a heterogeneous N-terminus and contains one amino acid substitution, namely asparagine for aspartic acid, at position 15 (gelsolin residue 187), that is due to a guanine-to-adenine transversion corresponding to nucleotide-654 of human plasma gelsolin cDNA. The substitution maps in a fragment with actin-binding activity and is located in a repetitive motif highly conserved among species. Thus FAF is the first human disease known to be caused by an internal abnormal degradation of a gelsolin variant. We designate this variant of gelsolin-associated amyloidosis ‘Agel Asn-187’.

scholarly journals eEF1A Isoforms Change in Abundance and Actin-Binding Activity during Maize Endosperm Development

2003 ◽  
Vol 133 (3) ◽  
pp. 1285-1295 ◽  
Author(s):  
Jose A. Lopez-Valenzuela ◽  
Bryan C. Gibbon ◽  
Peter A. Hughes ◽  
Theo W. Dreher ◽  
Brian A. Larkins
Keyword(s):  
Endosperm Development ◽  
Binding Activity ◽  
Actin Binding ◽  
Maize Endosperm

scholarly journals The Two ADF-H Domains of Twinfilin Play Functionally Distinct Roles in Interactions with Actin Monomers

2002 ◽  
Vol 13 (11) ◽  
pp. 3811-3821 ◽  
Author(s):  
Pauli J. Ojala ◽  
Ville O. Paavilainen ◽  
Maria K. Vartiainen ◽  
Roman Tuma ◽  
Alan G. Weeds ◽  
...  
Keyword(s):  
Binding Site ◽  
Binding Activity ◽  
Size Exclusion ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Actin Monomer ◽  
Wild Type ◽  
Native Page ◽  
Exclusion Chromatography

Twinfilin is a ubiquitous and abundant actin monomer–binding protein that is composed of two ADF-H domains. To elucidate the role of twinfilin in actin dynamics, we examined the interactions of mouse twinfilin and its isolated ADF-H domains with G-actin. Wild-type twinfilin binds ADP-G-actin with higher affinity (K D = 0.05 μM) than ATP-G-actin (K D = 0.47 μM) under physiological ionic conditions and forms a relatively stable (k off = 1.8 s−1) complex with ADP-G-actin. Data from native PAGE and size exclusion chromatography coupled with light scattering suggest that twinfilin competes with ADF/cofilin for the high-affinity binding site on actin monomers, although at higher concentrations, twinfilin, cofilin, and actin may also form a ternary complex. By systematic deletion analysis, we show that the actin-binding activity is located entirely in the two ADF-H domains of twinfilin. Individually, these domains compete for the same binding site on actin, but the C-terminal ADF-H domain, which has >10-fold higher affinity for ADP-G-actin, is almost entirely responsible for the ability of twinfilin to increase the amount of monomeric actin in cosedimentation assays. Isolated ADF-H domains associate with ADP-G-actin with rapid second-order kinetics, whereas the association of wild-type twinfilin with G-actin exhibits kinetics consistent with a two-step binding process. These data suggest that the association with an actin monomer induces a first-order conformational change within the twinfilin molecule. On the basis of these results, we propose a kinetic model for the role of twinfilin in actin dynamics and its possible function in cells.

scholarly journals Requirement of the F-actin-binding activity of l-afadin for enhancing the formation of adherens and tight junctions

2018 ◽  
Vol 23 (3) ◽  
pp. 185-199 ◽  
Author(s):  
Shotaro Sakakibara ◽  
Tomohiko Maruo ◽  
Muneaki Miyata ◽  
Kiyohito Mizutani ◽  
Yoshimi Takai
Keyword(s):  
Tight Junctions ◽  
Binding Activity ◽  
Actin Binding

scholarly journals Focal segmental glomerulosclerosis ACTN4 mutants binding to actin: regulation by phosphomimetic mutations

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hanshuang Shao ◽  
Bentley Wingert ◽  
Astrid Weins ◽  
Martin R. Pollak ◽  
Carlos Camacho ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Focal Segmental Glomerulosclerosis ◽  
Actin Filaments ◽  
Binding Activity ◽  
Binding Domain ◽  
Actin Binding ◽  
Dominant Form ◽  
Cell Functions ◽  
Segmental Glomerulosclerosis ◽  
Actin Binding Domain

Abstract Natural mutations such as lysine 255 to glutamic acid (K to E), threonine 259 to isoleucine (T to I) and serine 262 to proline (S to P) that occur within the actin binding domain of alpha-actinin-4 (ACTN4) cause an autosomal dominant form of focal segmental glomerulosclerosis (FSGS) in affected humans. This appears due to elevated actin binding propensity in podocytes resulting in a ‘frozen’ cytoskeleton. What is challenging is how this cellular behavior would be compatible with other cell functions that rely on cytoskeleton plasticity. Our previous finding revealed that wild type ACTN4 can be phosphorylated at tyrosine 4 and 31 upon stimulation by epidermal growth factor (EGF) to reduce the binding to actin cytoskeleton. We queried whether the elevated actin binding activity of FSGS mutants can be downregulated by EGF-mediated phosphorylation, to discern a mechanism by which the actin-cytoskeleton can be released in FSGS. In this manuscript, we first constructed variants with Y4/31E to mimic the phosphorylation at tyrosines 4 and 31 based on earlier modeling simulations that predicted that this would bury the actin binding domains and lead to a decrease in actin binding activity. We found that Y4/31E significantly reduced the actin binding activity of K255E, T259I and S262P, dramatically preventing them from aggregating in, and inhibiting motility of, podocytes, fibroblasts and melanoma cells. A putative kinase target site at Y265 in the actin binding domain was also generated as a phosphomimetic ACTN4 Y265E that demonstrated even greater binding to actin filaments than K255E and the other FSGS mutants. That the tyrosine kinase regulation of FSGS mutation binding to actin filaments can occur in cells was shown by phosphorylation on Y4 and Y31 of the K225E after extended exposure of cells to EGF, with a decrease in ACTN4 aggregates in fibroblasts. These findings will provide evidence for targeting the N-termini of FSGS ACTN4 mutants to downregulate their actin binding activities for ameliorating the glomerulosclerotic phenotype of patients.

scholarly journals EPLIN regulates actin dynamics by cross-linking and stabilizing filaments

2003 ◽  
Vol 160 (3) ◽  
pp. 399-407 ◽  
Author(s):  
Raymond S. Maul ◽  
Yuhong Song ◽  
Kurt J. Amann ◽  
Sachi C. Gerbin ◽  
Thomas D. Pollard ◽  
...  
Keyword(s):  
Actin Filament ◽  
Actin Polymerization ◽  
Binding Activity ◽  
Stress Fibers ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Membrane Ruffling ◽  
Cross Links ◽  
As Stress ◽  
Kinetics Of

Epithelial protein lost in neoplasm (EPLIN) is a cytoskeleton-associated protein encoded by a gene that is down-regulated in transformed cells. EPLIN increases the number and size of actin stress fibers and inhibits membrane ruffling induced by Rac. EPLIN has at least two actin binding sites. Purified recombinant EPLIN inhibits actin filament depolymerization and cross-links filaments in bundles. EPLIN does not affect the kinetics of spontaneous actin polymerization or elongation at the barbed end, but inhibits branching nucleation of actin filaments by Arp2/3 complex. Side binding activity may stabilize filaments and account for the inhibition of nucleation mediated by Arp2/3 complex. We propose that EPLIN promotes the formation of stable actin filament structures such as stress fibers at the expense of more dynamic actin filament structures such as membrane ruffles. Reduced expression of EPLIN may contribute to the motility of invasive tumor cells.

Human Plasma Gelsolin Inhibits Cellular Responses to Platelet Activating Factor (PAF).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3568-3568
Author(s):  
Teresia A. Magnuson-Osborn ◽  
Claes Dahlgren ◽  
John H. Hartwig ◽  
Thomas P. Stossel
Keyword(s):  
Platelet Activating Factor ◽  
Actin Binding ◽  
Major Surgery ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Cellular Activation ◽  
Blood Concentrations ◽  
Plasma Gelsolin ◽  
Molar Excess

Abstract Gelsolin is a highly conserved intracellular actin-binding protein with an extracellular isoform named plasma gelsolin (pGSN). Relatively high (250 mg /L) blood concentrations of pGSN decrease in response to trauma, major surgery, sepsis, burns, ionizing radiation, and hyperoxia. Depletion of pGSN to a critical (~20%) level precedes and predicts complications of primary injuries such as lung permeability changes, ARDS, assisted ventilation and death. Administration of recombinant pGSN ameliorates such complications and reduces mortality in animal models. A proposed mechanism for pGSN’s protective effects is that it inhibits inflammatory mediators generated during primary injuries, since pGSN binds bioactive mediators, including lysophospatidic acid (LPA) and endotoxin in vitro. Because of its structural similarity we hypothesized that plasma gelsolin binds also to the potent lipid mediator platelet activating factor (PAF) and report here on the inhibition of PAF-induced cellular activation. Recombinant pGSN inhibited PAF-induced P-selectin up-regulation by human platelets as measured by flow cytometry. A ten- to 40-fold molar excess (0.5–20 μM) of pGSN over PAF inhibits P-selectin expression by 40 to 80%. The concentrations of plasma gelsolin used approximate the ~2–3 μM concentrations in plasma, and the molar excess of pGSN over PAF is probably greater in biological systems, where PAF has nanomolar affinity for its receptor. pGSN also inhibited PAF-induced superoxide anion (O2-) production (measured by chemiluminescence) of human neutrophils (PMN) in a concentration-dependent manner. The inhibition was up to 80% at a concentration of 10 μM (tenfold molar excess over PAF). A phospholipid-binding peptide derived from pGSN (QRLFQVKGRR) also inhibited PAF-mediated O2- generation by PMN. The inhibition was 65% at a 1:1 molar ratio (1 μM). In conclusion pGSN interferes with PAF-induced cellular activation in vitro, suggesting a mechanism for the protective role of plasma gelsolin that has been observed in vivo.

Recombinant plasma gelsolin infusion attenuates burn-induced pulmonary microvascular dysfunction

2004 ◽  
Vol 96 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Patricia A. Rothenbach ◽  
Benny Dahl ◽  
Jason J. Schwartz ◽  
Grant E. O'Keefe ◽  
Masaya Yamamoto ◽  
...  
Keyword(s):  
Burn Injury ◽  
Plasma Concentrations ◽  
Early Time ◽  
Microvascular Dysfunction ◽  
Microvascular Permeability ◽  
Lung Model ◽  
Actin Binding ◽  
Sprague Dawley ◽  
Plasma Gelsolin ◽  
Perfused Lung

Reduced plasma concentrations of the extracellular actin-binding proteins gelsolin and Gc-globulin correlate with pulmonary failure and death in humans after injury. The purpose of this study was to investigate the role of plasma gelsolin in the pathophysiology of inflammation-induced lung injury. We postulated that plasma gelsolin levels decrease at an early time point after burn injury and that the intravenous infusion of gelsolin prevents burn-induced pulmonary microvascular dysfunction. Adult Sprague-Dawley rats were randomized to undergo a 40% body surface area thermal injury (Burn) or manipulation without burn (Sham). Plasma gelsolin and Gc-globulin concentrations were determined at various times during the first 6 days of injury by Western blotting. Other animals were randomized to receive either recombinant human gelsolin (0.078, 0.78, or 7.8 mg) or albumin (7.8 mg) before and 8 h after Burn or Sham. Twenty-four hours later, pulmonary microvascular permeability was assessed by measuring the capillary filtration by use of an isolated, perfused lung model. We found that plasma gelsolin levels of burn-injured rats decreased to 10% of normal levels within 12 h and remained below normal levels for up to 6 days postinjury. Gc-globulin values also fall, but to a lesser extent and only transiently. Treatment of burned animals with intravenous infusions of recombinant human gelsolin prevented the increase in pulmonary microvascular permeability that accompanies this injury. Our findings are consistent with the hypothesis that plasma gelsolin depletion contributes to the pathophysiology of pulmonary microvascular dysfunction during inflammation.

scholarly journals Interaction between Mitochondria and the Actin Cytoskeleton in Budding Yeast Requires Two Integral Mitochondrial Outer Membrane Proteins, Mmm1p and Mdm10p

1998 ◽  
Vol 141 (6) ◽  
pp. 1371-1381 ◽  
Author(s):  
Istvan Boldogh ◽  
Nikola Vojtov ◽  
Sharon Karmon ◽  
Liza A. Pon
Keyword(s):  
Membrane Proteins ◽  
Actin Cytoskeleton ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Protein S ◽  
Binding Activity ◽  
Actin Binding ◽  
Mitochondrial Outer Membrane ◽  
Mitochondrial Movement ◽  
Mitochondrial Motility

Transfer of mitochondria to daughter cells during yeast cell division is essential for viable progeny. The actin cytoskeleton is required for this process, potentially as a track to direct mitochondrial movement into the bud. Sedimentation assays reveal two different components required for mitochondria–actin interactions: (1) mitochondrial actin binding protein(s) (mABP), a peripheral mitochondrial outer membrane protein(s) with ATP-sensitive actin binding activity, and (2) a salt-inextractable, presumably integral, membrane protein(s) required for docking of mABP on the organelle. mABP activity is abolished by treatment of mitochondria with high salt. Addition of either the salt-extracted mitochondrial peripheral membrane proteins (SE), or a protein fraction with ATP-sensitive actin-binding activity isolated from SE, to salt-washed mitochondria restores this activity. mABP docking activity is saturable, resistant to high salt, and inhibited by pre-treatment of salt-washed mitochondria with papain. Two integral mitochondrial outer membrane proteins, Mmm1p (Burgess, S.M., M. Delannoy, and R.E. Jensen. 1994. J.Cell Biol. 126:1375–1391) and Mdm10p, (Sogo, L.F., and M.P. Yaffe. 1994. J.Cell Biol. 126:1361– 1373) are required for these actin–mitochondria interactions. Mitochondria isolated from an mmm1-1 temperature-sensitive mutant or from an mdm10 deletion mutant show no mABP activity and no mABP docking activity. Consistent with this, mitochondrial motility in vivo in mmm1-1 and mdm10Δ mutants appears to be actin independent. Depolymerization of F-actin using latrunculin-A results in loss of long-distance, linear movement and a fivefold decrease in the velocity of mitochondrial movement. Mitochondrial motility in mmm1-1 and mdm10Δ mutants is indistinguishable from that in latrunculin-A–treated wild-type cells. We propose that Mmm1p and Mdm10p are required for docking of mABP on the surface of yeast mitochondria and coupling the organelle to the actin cytoskeleton.

Sign in / Sign up

Export Citation Format

Share Document