title: Interleukin-1β effect on the endogenous ADP-ribosylation and phosphorylation of eukaryotic elongation factor 2.
abstract: Eukaryotic elongation factor 2 (eEF2) plays an important role in eukaryotic polypeptide chain elongation. Adenosine diphosphate (ADP)-ribosylation is a post-translational modification reaction that catalyzes the transfer of ADP-ribose group to eEF2 and this causes the inhibition of protein synthesis. Indeed, in the absence of diptheria toxin, endogenous ADP-ribosylation can occur. eEF2 is phosphorylated by eEF2 kinase which prevents binding to ribosomes thus inhibiting its activity. Increase in endogenous ADP-ribosylation level approximately 70-75 % was observed in IL-1β treated HUVECs. Moreover, a 70 % rise of phosphorylation of eEF2 was measured. Alteration of endogenous ADP-ribosylation of eEF2 activity was related with cellular mono-ADP-ribosyltransferases (ADPrT). Increment of endogenous ADP-ribosylation on eEF2 did not seem to occur as a direct effect of IL-1β; it arises from the activation of ADPrT. This 2.5 fold increase was abolished by ADPrT inhibitors. Due to these post-translational modifications, global protein synthesis is inhibited. After dephosphorylation of phospho-eEF2, around 20 % increase in protein synthesis was observed. In conclusion, systemic IL-1β has an important role in the regulation of global protein synthesis.
authors: Department of Biophysics, Istanbul Faculty of Medicine, Istanbul University, 34390, Çapa, Istanbul, Turkey.|Department of Physiology, Faculty of Medicine, Istanbul Bilim University, 34394, Esentepe, Istanbul, Turkey.
authors: Ebru
authors: E
authors: Hacıosmanoğlu
authors: Department of Biophysics, Istanbul Faculty of Medicine, Istanbul University, 34390, Çapa, Istanbul, Turkey. basakgn@yahoo.com.
authors: Başak
authors: B
authors: Varol
authors: Department of Biophysics, Istanbul Faculty of Medicine, Istanbul University, 34390, Çapa, Istanbul, Turkey.
authors: Bilge Özerman
authors: BÖ
authors: Edis
authors: Department of Biophysics, Istanbul Faculty of Medicine, Istanbul University, 34390, Çapa, Istanbul, Turkey.
authors: Muhammet
authors: M
authors: Bektaş
keywords: Diphtheria toxin; Endogenous ADP-ribosylation; Eukaryotic elongation factor 2; Interleukin-1β; Phosphorylation; Protein synthesis