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

The integration of mutant loci affecting maize endosperm development in a dense genetic map using an AFLP-based procedure

2008 ◽  
Vol 22 (4) ◽  
pp. 527-541 ◽  
Author(s):  
Luca Pasini ◽  
Maria Rosaria Stile ◽  
Enrico Puja ◽  
Rita Valsecchi ◽  
Priscilla Francia ◽  
...  
Keyword(s):  
Genetic Map ◽  
Endosperm Development ◽  
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 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 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.

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