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EF-2

Page updated 4/6/03

Like other components of the translation machinery (EF-1a and EF1b), EF-2 is an actin binding protein. An interaction was first indicated by immunofluorescence co-localisation of EF-2 with F-actin in fibroblasts (Shestokova, et al, 1991,1993a, b), and later confirmed by co-sedimentation assay (Bektas et al, 1994).  Binding of EF-2 was reported to be increased two-fold (Fig.1 in Bektas et al, 1994 although elsewhere in the paper the authors claim 4 fold?) in the presence of GTPgS.  Binding to F-actin had a Kd of 0.85mM (micromolar) and was inhibited by G-actin indicating that EF-2 also binds G-actin.  Competition between EF-2 and EF-1a was observed.  EF-2 may bind actin through sub-domain 2 as EF-2 competes with DNAse1 for binding (Bektas et al, 1998).  Indirect effects are also possible as is the case for profilin.  Diphtheria toxin catalyses the transfer of an ADP-ribosyl group from NAD+ to EF-2 and prevents protein synthesis, but this neither prevents EF-2 being localized to F-actin in cells (Shestakova et al, 1993) or affect F-actin binding in vitro (Bektas et al, 1994). 

References:-

Bektas, M., R. Nurten, et al. (1994). “Interactions of eukaryotic elongation factor 2 with actin: a possible link between protein synthetic machinery and cytoskeleton.” FEBS letters 356, 89-93.

Bektas, M., Nurten, R., Sayers, Z. & Bermek, E. (1998). “Interactions of elongation factor 2 with the cytoskeleton and interference with DNase I binding to actin.” Eur.J.Biochem. 256, 142-147.

Shestakova, E. A., Motuz, L. P., Minin, A. A., Gelfand, V. I. & Gavrilova, L. P. (1991) Some of eukaryotic elongation factor 2 is localized with actin microfilament bundles in mouse embryo fibroblasts. Cell Biol.Int.Rep. 15, 75-84.

Shestakova, E. A., Motuz, L. P., Minin, A. A. & Gavrilova, L. P. (1993a) Study of localization of the protein-synthesizing machinery along actin actin filament bundles., Cell Biol.International. 17, 409-416.

Shestakova, E. A., Motuz, L. P. & Gavrilova, L. P. (1993b) Co-localization of components of the protein-synthesizing machinery with the cytoskeleton in G0-arrested cells. Cell Biol.International. 17, 417-424.

Watanabe, S., Sakurai, K., Amagai, A. & Maseda, Y. (2003) Unexpected roles of a Dictyostelium homologue of eukaryotic EF-2 in growth and differentiation. J Cell Sci. 116, 2647-2654.

 
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