scholarly journals Bundling of actin filaments by elongation factor 1 alpha inhibits polymerization at filament ends.

1996 ◽  
Vol 135 (5) ◽  
pp. 1309-1321 ◽  
Author(s):  
J W Murray ◽  
B T Edmonds ◽  
G Liu ◽  
J Condeelis
Keyword(s):  
Actin Filaments ◽  
Actin Polymerization ◽  
Elongation Factor ◽  
Protein Translation ◽  
Binding Activity ◽  
Dependent Manner ◽  
Molar Ratios ◽  
Elongation Factor 1 Alpha ◽  
Elongation Factor 1

Elongation factor 1 alpha (EF1 alpha) is an abundant protein that binds aminoacyl-tRNA and ribosomes in a GTP-dependent manner. EF1 alpha also interacts with the cytoskeleton by binding and bundling actin filaments and microtubules. In this report, the effect of purified EF1 alpha on actin polymerization and depolymerization is examined. At molar ratios present in the cytosol, EF1 alpha significantly blocks both polymerization and depolymerization of actin filaments and increases the final extent of actin polymer, while at high molar ratios to actin, EF1 alpha nucleates actin polymerization. Although EF1 alpha binds actin monomer, this monomer-binding activity does not explain the effects of EF1 alpha on actin polymerization at physiological molar ratios. The mechanism for the inhibition of polymerization is related to the actin-bundling activity of EF1 alpha. Both ends of the actin filament are inhibited for polymerization and both bundling and the inhibition of actin polymerization are affected by pH within the same physiological range; at high pH both bundling and the inhibition of actin polymerization are reduced. Additionally, it is seen that the binding of aminoacyl-tRNA to EF1 alpha releases EF1 alpha's inhibiting effect on actin polymerization. These data demonstrate that EF1 alpha can alter the assembly of F-actin, a filamentous scaffold on which non-membrane-associated protein translation may be occurring in vivo.

scholarly journals The mechanisms of dynamin-actin interaction

2019 ◽  
Author(s):  
Ruihui Zhang ◽  
Nathalie Gerassimov ◽  
Donghoon M. Lee ◽  
John R. Jimah ◽  
Sangjoon Kim ◽  
...  
Keyword(s):  
Cell Fusion ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Electron Tomography ◽  
Dependent Manner ◽  
Actin Network ◽  
Independent Manner ◽  
Rich Domain ◽  
Cell Cell

AbstractCell-cell fusion is an indispensable process in the conception, development and physiology of multicellular organisms. Here we demonstrate a direct and noncanonical role for dynamin, best known as a fission GTPase in endocytosis, in cell-cell fusion. Our genetic and cell biological analyses show that dynamin colocalizes within the F-actin-enriched podosome-like structures at the fusogenic synapse, which is required for generating invasive membrane protrusions and myoblast fusion in vivo, in an endocytosis-independent manner. Biochemical, negative stain EM and cryo-electron tomography (cryo-ET) analyses revealed that dynamin forms helices that directly bundles actin filaments by capturing multiple actin filaments at their outer rim via interactions with dynamin’s proline-rich domain. GTP hydrolysis by dynamin triggers disassembly of the dynamin helix, exposes the sides of the actin filaments, promotes dynamic Arp2/3-mediated branched actin polymerization, and generates a mechanically stiff actin network. Thus, dynamin functions as a unique actin-bundling protein that enhances mechanical force generation by the F-actin network in a GTPase-dependent manner. Our findings have universal implications for understanding dynamin-actin interactions in various cellular processes beyond cell-cell fusion.

Elongation factor-1 alpha is an overexpressed actin binding protein in metastatic rat mammary adenocarcinoma

1996 ◽  
Vol 109 (11) ◽  
pp. 2705-2714 ◽  
Author(s):  
B.T. Edmonds ◽  
J. Wyckoff ◽  
Y.G. Yeung ◽  
Y. Wang ◽  
E.R. Stanley ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Elongation Factor ◽  
Metastatic Potential ◽  
Cell Types ◽  
Binding Activity ◽  
Mammary Adenocarcinoma ◽  
Actin Binding ◽  
Filamentous Actin ◽  
Elongation Factor 1 Alpha ◽  
Elongation Factor 1

Overexpression of elongation factor-1 alpha (EF1 alpha) mRNA has been correlated with increased metastatic potential in mammary adenocarcinoma; however, this relationship was not explored at the level of protein expression. As EF1 alpha has been shown in other cell types to be a component of the actin cytoskeleton, a likely effector in metastasis, the actin binding activity of EF1 alpha from metastatic and nonmetastatic rat breast tumors and cell lines was investigated. We have shown that EF1 alpha protein is overexpressed in metastatic compared to nonmetastatic cells and whole tumors. Similarly to other EF1 alpha s, both types of tumor EF1 alpha bind to F-actin, but EF1 alpha from metastatic cells has a reduced affinity for actin. In addition, there is a high correlation between the intracellular distribution of filamentous actin and EF1 alpha in those cytoskeletal structures thought to be important for supporting the cellular motility required for metastasis. Following stimulation with EGF, there is a parallel increase in the amount of F-actin and EF1 alpha associated with the cytoskeleton. The response to EGF can be blocked with cytochalasin D indicating that the binding of EF1 alpha to the cytoskeleton is mediated by F-actin. We propose that a weakened association of EF1 alpha with actin may be related to the metastatic process via an altered organization of the actin cytoskeleton and the differential translation of mRNAs associated with the cytoskeleton.

scholarly journals Cloning, nucleotide sequence, and expression of one of two genes coding for yeast elongation factor 1 alpha.

1985 ◽  
Vol 260 (5) ◽  
pp. 3090-3096
Author(s):  
P Cottrelle ◽  
D Thiele ◽  
V L Price ◽  
S Memet ◽  
J Y Micouin ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Elongation Factor ◽  
Elongation Factor 1 Alpha ◽  
Elongation Factor 1

scholarly journals EEF1A2 interacts with HSP90AB1 to promote lung adenocarcinoma metastasis via enhancing TGF-β/SMAD signalling

2021 ◽  
Author(s):  
Liqing Jia ◽  
Xiaolu Ge ◽  
Chao Du ◽  
Linna Chen ◽  
Yanhong Zhou ◽  
...  
Keyword(s):  
Lung Adenocarcinoma ◽  
Protein Interactions ◽  
Elongation Factor ◽  
Protein Translation ◽  
Protein Protein Interactions ◽  
Promising Target ◽  
Tgfβ Receptor ◽  
Mesenchymal Transformation

Abstract Background Eukaryotic protein translation elongation factor 1α2 (EEF1A2) is an oncogene that promotes the progression of breast and pancreatic cancer. In this study, we aimed to elucidate the oncogenic function of EEF1A2 in the metastasis of lung adenocarcinoma (LUAD). Methods Immunohistochemistry and western blot were used to study EEF1A2 expression levels in LUAD tissues and cells, respectively. The role of EEF1A2 in LUAD progression were investigated in vitro and in vivo. We identified potential EEF1A2-binding proteins by liquid chromatography-electrospray mass spectrometry (LC-MS)/MS. Protein–protein interactions were determined by immunofluorescence and co-immunoprecipitation (Co-IP). Results In this study, we report that EEF1A2 mediates the epithelial–mesenchymal transformation (EMT), to promote the metastasis of LUAD cells in vitro and in vivo. Moreover, EEF1A2 interacts with HSP90AB1 to increase TGFβ Receptor (TβR)-I, and TβRII expression, followed by enhanced SMAD3 and pSMAD3 expression and nuclear localisation, which promotes the EMT of LUAD cells. Overexpression of EEF1A2 in cancer tissues is associated with poor prognosis and short survival of patients with LUAD. Conclusions These findings underscore the molecular functions of EEF1A2 in LUAD metastasis and indicate that EEF1A2 represents a promising target in the treatment of aggressive LUAD.

scholarly journals A higher plant extracellular vitronectin-like adhesion protein is related to the translational elongation factor-1 alpha.

1994 ◽  
Vol 6 (3) ◽  
pp. 393-404 ◽  
Author(s):  
J K Zhu ◽  
B Damsz ◽  
A K Kononowicz ◽  
R A Bressan ◽  
P M Hasegawa
Keyword(s):  
Elongation Factor ◽  
Higher Plant ◽  
Adhesion Protein ◽  
Elongation Factor 1 Alpha ◽  
Elongation Factor 1

Fibrinogen binding to the integrin αIIbβ3 modulates store-mediated calcium entry in human platelets

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2648-2656 ◽  
Author(s):  
Juan A. Rosado ◽  
Else M. Y. Meijer ◽  
Karly Hamulyak ◽  
Irena Novakova ◽  
Johan W. M. Heemskerk ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Integrin Αiibβ3 ◽  
Fibrinogen Binding

Abstract Effects of the occupation of integrin αIIbβ3 by fibrinogen on Ca++signaling in fura-2–loaded human platelets were investigated. Adding fibrinogen to washed platelet suspensions inhibited increases in cytosolic [Ca++] concentrations ([Ca++]i) evoked by adenosine diphosphate (ADP) and thrombin in a concentration-dependent manner in the presence of external Ca++ but not in the absence of external Ca++ or in the presence of the nonselective cation channel blocker SKF96365, indicating selective inhibition of Ca++entry. Fibrinogen also inhibited store-mediated Ca++ entry (SMCE) activated after Ca++ store depletion using thapsigargin. The inhibitory effect of fibrinogen was reversed if fibrinogen binding to αIIbβ3 was blocked using RDGS or abciximab and was absent in platelets from patients homozygous for Glanzmann thrombasthenia. Fibrinogen was without effect on SMCE once activated. Activation of SMCE in platelets occurs through conformational coupling between the intracellular stores and the plasma membrane and requires remodeling of the actin cytoskeleton. Fibrinogen inhibited actin polymerization evoked by ADP or thapsigargin in control cells and in cells loaded with the Ca++ chelator dimethyl BAPTA. It also inhibited the translocation of the tyrosine kinase p60src to the cytoskeleton. These results indicate that the binding of fibrinogen to integrin αIIbβ3 inhibits the activation of SMCE in platelets by a mechanism that may involve modulation of the reorganization of the actin cytoskeleton and the cytoskeletal association of p60src. This action may be important in intrinsic negative feedback to prevent the further activation of platelets subjected to low-level stimuli in vivo.

Amanita griseofusca: A new species of Amanita in section Vaginatae from Malam Jabba, Swat, Pakistan

Phytotaxa ◽  
2018 ◽  
Vol 364 (2) ◽  
pp. 181 ◽  
Author(s):  
MUNAZZA KIRAN ◽  
JUNAID KHAN ◽  
HASSAN SHER ◽  
DONALD H. PFISTER ◽  
ABDUL NASIR KHALID
Keyword(s):  
New Species ◽  
Elongation Factor ◽  
Molecular Data ◽  
Internal Transcribed Spacer Region ◽  
Translation Elongation ◽  
Elongation Factor 1 Alpha ◽  
Pileus Surface ◽  
Elongation Factor 1 ◽  
A New Species ◽  
Partial Translation

A new species, Amanita griseofusca in section Vaginatae is described and illustrated here from Pakistan. Distinguishing characters of the new species include medium-sized basidiomata, greyish brown pileus surface with white to beige, membranous volval remnants present as one (large) to a few (small) warts, close lamellae which are cream colored with a pink tone, striations one third of the total pileus radius, broadly ellipsoidal to ellipsoidal basidiospores and white loose saccate volva turning beige at maturity. Molecular data inferred from partial nuc rDNA internal transcribed spacer region (ITS), partial nuc rDNA larger subunit region (LSU) and partial translation elongation factor 1-alpha (tef1) confirms the novelty of the present taxon.

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