Some of eukaryotic elongation factor 2 is colocalized with actin microfilament bundles in mouse embryo fibroblasts

Shestakova, Elena; Motuz, L.P.; Минин, А. А.; Gelfand, Vladimir I.; Gavrilova, L. P.

doi:10.1016/0309-1651(91)90084-v

Cited by 30 publications

(26 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dephosphorylated state is the active form (Ryazanov et al, 1988 III, known as EF-2 kinase (Nairn and Palfrey, 1987), and dephosphorylated by PP2A (phosphatase 2A) (Michael et al, 1989). EF-2 is also known to be a GTP-binding protein (Kohno et al, 1986) and is colocalized with actin (Shestakova et al, 1991;Bektas et al, 1994). Surprisingly, the present work using Dd-EF2-null cells has revealed that the 101 kDa phosphoprotein is not required for protein synthesis and cell proliferation but it is involved in cytokinesis and the growth to differentiation transition.…”

Section: Introductioncontrasting

confidence: 58%

“…Positive participation of 101 kDa Dd-EF2H in the process of cytokinesis would be a novel function. In connection with this, some of eukaryotic EF-2 is known to be colocalized with actin microfilament bundles in mouse embryo fibroblasts, which suggests a possible link between the protein synthetic machinery and the cytoskeleton (Shestakova et al, 1991;Bektas et al, 1994).…”

Section: Discussionmentioning

confidence: 80%

See 1 more Smart Citation

Unexpected roles of aDictyosteliumhomologue of eukaryotic EF-2 in growth and differentiation

Watanabe

Sakurai

Amagai

et al. 2003

Journal of Cell Science

View full text Add to dashboard Cite

EF-2 is believed to be indispensable for polypeptide chain elongation in protein synthesis and therefore for cell proliferation. Surprisingly, we could isolate ef2 null cells from Dictyostelium discoideum that exhibited almost normal growth and protein synthesis, which suggests that there is another molecule capable of compensating for EF-2 function. The knock-out of Dictyostelium EF-2 (Dd-EF2H; 101 kDa phosphoprotein)impairs cytokinesis, resulting in formation of multinucleate cells. The initiation of differentiation, including the acquisition of aggregation competence, was delayed in Dd-ef2 null cells compared with that in wild-type. By contrast, Dd-ef2 overexpression enhanced the progression of differentiation, thus indicating a positive involvement of Dd-EF2H in growth/differentiation transition.

show abstract

Section: Introductioncontrasting

confidence: 58%

Section: Discussionmentioning

confidence: 80%

Unexpected roles of aDictyosteliumhomologue of eukaryotic EF-2 in growth and differentiation

Watanabe

Sakurai

Amagai

et al. 2003

Journal of Cell Science

View full text Add to dashboard Cite

show abstract

“…Early cell ultrastructural studies revealed an association between components of the translational machinery and the actin cytoskeleton (4,5), and functional studies showed that mRNAs associated with detergent-insoluble material, presumably the cytoskeleton, are translated more efficiently (6). Subsequently, it has been shown that virtually all of the protein components of translation associate with the cytoskeleton in situ (7)(8)(9)(10)(11)(12); however, no direct effect of the cytoskeleton on the specific activity of any of these co-factors has been demonstrated.…”

mentioning

confidence: 99%

The Effect of F-actin on the Binding and Hydrolysis of Guanine Nucleotide by Dictyostelium Elongation Factor 1A

Edmonds¹,

Bell²,

Wyckoff³

et al. 1998

Journal of Biological Chemistry

View full text Add to dashboard Cite

Indirect evidence implicates actin as a cofactor in eukaryotic protein synthesis. The present study directly examines the effects of F-actin on the biochemical properties of eukaryotic elongation factor 1A (eEF1A, formerly EF1␣), a major actin-binding protein. The basal mechanism of eEF1A alone is determined under physiological conditions with the critical finding that glycerol and guanine nucleotide are required to prevent protein aggregation and loss of enzymatic activity. The dissociation constants (K d ) for GDP and GTP are 2.5 M and 0.6 M, respectively, and the k cat of GTP hydrolysis is 1.0 ؋ 10 ؊3 s ؊1 . When eEF1A binds to F-actin, there is a 7-fold decrease in the affinity for guanine nucleotide and an increase of 35% in the rate of GTP hydrolysis. Based upon our results and the relevant cellular concentrations, the predominant form of cellular eEF1A is calculated to be GTP⅐eEF1A⅐F-actin. We conclude that Factin does not significantly modulate the basal enzymatic properties of eEF1A; however, actin may still influence protein synthesis by sequestering GTP⅐eEF1A away from interactions with its known translational ligands, e.g. aminoacyl-tRNA and ribosomes.Actin has been implicated as a co-factor in eukaryotic protein synthesis (reviewed in Refs. 1-3). Early cell ultrastructural studies revealed an association between components of the translational machinery and the actin cytoskeleton (4, 5), and functional studies showed that mRNAs associated with detergent-insoluble material, presumably the cytoskeleton, are translated more efficiently (6). Subsequently, it has been shown that virtually all of the protein components of translation associate with the cytoskeleton in situ (7-12); however, no direct effect of the cytoskeleton on the specific activity of any of these co-factors has been demonstrated.Eukaryotic elongation factor 1A (eEF1A, 1 formerly EF1␣) 2 is the most abundant G protein in cells, comprising 1-5% of total cell protein (14 -16). The principal role of eEF1A during protein synthesis is to bind aminoacyl-tRNA to the A-site of the ribosome by a GTP-dependent mechanism (17). Following the hydrolysis of GTP, aminoacyl-tRNA is incorporated into the growing polypeptide, and GDP⅐eEF1A is released from the ribosome. The exchange of bound GDP for free GTP regenerates the capacity of eEF1A to bind another aminoacyl-tRNA and to participate in further cycles of elongation. Therefore, the affinity of eEF1A for GDP and GTP and the kinetics of GTP hydrolysis are potential targets for ligands operating through eEF1A to regulate protein synthesis. For example, the rate of GDP/ GTP exchange by eEF1A in vitro is too slow to support the measured rate of polypeptide elongation in vivo; therefore, the need for a nucleotide exchange factor has been postulated (18,19).eEF1A was identified in a screen for actin binding proteins in Dictyostelium and was shown to bind both monomeric and filamentous actin (F-actin) in vitro and in situ (20 -23). Due to the striking similarity of eEF1A primary sequences among species, it...

show abstract

“…A less well understood class of interactions involves association of the components of the cytoskeleton with the protein synthetic machinery. These include interactions of tubulin with EF-1A (Marchesi and Ngo, 1993;Durso and Cyr, 1994;Shiina et al, 1994) and interactions of actin filaments with the elongation factors 1A and 2 (Matsudaira, 1991;Yang et al, 1990;Demma et al, 1990;Dharmwardhane et al, 1991 ;Marchesi and Ngo, 1993;Edmonds, 1993;Gavrilova et al, 1987;Shestakova et al, 1991;Bektas , et al, 1994). In the present study, a combination of techniques were employed to characterise in vitro EF-2 and actin interactions and the interaction products.…”

Section: Discussionmentioning

confidence: 97%

“…In particular, a major actin-binding protein ABP-50 was discovered to be elongation factor 1A (EF-1A; Matsudaira, 1991;Yang et al, 1990;Demma et al, 1990;Dharmwardhane et al, 1991;Marchesi and Ngo, 1993;Edmonds, 1993). The presence of elongation factor 2 (EF-2) along actin microfilament bundles was shown using immunofluorescence microscopy (Gavrilova et al, 1987;Shestakova et al, 1991) and interactions between F-actin and EF-2 in vitro were demonstrated in co-sedimentation experiments (Bektas , et al, 1994). A stoichiometry of 0.12 EF-2/F-actin subunit was found at saturation levels, with the results suggesting binding at a single type of site with an apparent dissociation constant of 0.85 µM.…”

mentioning

confidence: 99%

Interactions of elongation factor 2 with the cytoskeleton and interference with DNase I binding to actin

Bektaş

Nurten

Sayers

et al. 1998

European Journal of Biochemistry

View full text Add to dashboard Cite

Interactions of elongation factor 2 (EF‐2) with G‐actin and F‐actin in vitro were investigated using viscosimetry, gel filtration and electron microscopy. Under depolymerization conditions, at a molar ratio of 0.5 : 1 (EF‐2/F‐actin subunit), F‐actin is stabilised by EF‐2 and filaments depolymerize about three times slower than control solutions containing only F‐actin. Filament stability is improved also when EF2 is included in the solution in the presence of DNase I. Electron micrographs and viscosity measurements indicate that EF‐2 may support small bundles with a width of 2 or 3 filaments. It was established that EF‐2 interacts with G‐actin in vitro, and reduces G‐actin inhibition of DNase I activity when it is present at a ratio of 1 : 1. Results are discussed in the context of possible functional significance of the interactions.

show abstract

Some of eukaryotic elongation factor 2 is colocalized with actin microfilament bundles in mouse embryo fibroblasts

Cited by 30 publications

References 14 publications

Unexpected roles of aDictyosteliumhomologue of eukaryotic EF-2 in growth and differentiation

Unexpected roles of aDictyosteliumhomologue of eukaryotic EF-2 in growth and differentiation

The Effect of F-actin on the Binding and Hydrolysis of Guanine Nucleotide by Dictyostelium Elongation Factor 1A

Interactions of elongation factor 2 with the cytoskeleton and interference with DNase I binding to actin

Contact Info

Product

Resources

About