Raf kinases mediate the phosphorylation of eukaryotic translation elongation factor 1A and regulate its stability in eukaryotic cells

Please always quote using this URN: urn:nbn:de:bvb:20-opus-124149
  • We identified eukaryotic translation elongation factor 1A (eEF1A) Raf-mediated phosphorylation sites and defined their role in the regulation of eEF1A half-life and of apoptosis of human cancer cells. Mass spectrometry identified in vitro S21 and T88 as phosphorylation sites mediated by B-Raf but not C-Raf on eEF1A1 whereas S21 was phosphorylated on eEF1A2 by both B- and C-Raf. Interestingly, S21 belongs to the first eEF1A GTP/GDP-binding consensus sequence. Phosphorylation of S21 was strongly enhanced when both eEF1A isoforms were preincubatedWe identified eukaryotic translation elongation factor 1A (eEF1A) Raf-mediated phosphorylation sites and defined their role in the regulation of eEF1A half-life and of apoptosis of human cancer cells. Mass spectrometry identified in vitro S21 and T88 as phosphorylation sites mediated by B-Raf but not C-Raf on eEF1A1 whereas S21 was phosphorylated on eEF1A2 by both B- and C-Raf. Interestingly, S21 belongs to the first eEF1A GTP/GDP-binding consensus sequence. Phosphorylation of S21 was strongly enhanced when both eEF1A isoforms were preincubated prior the assay with C-Raf, suggesting that the eEF1A isoforms can heterodimerize thus increasing the accessibility of S21 to the phosphate. Overexpression of eEF1A1 in COS 7 cells confirmed the phosphorylation of T88 also in vivo. Compared with wt, in COS 7 cells overexpressed phosphodeficient (A) and phospho-mimicking (D) mutants of eEF1A1 (S21A/D and T88A/D) and of eEF1A2 (S21A/D), resulted less stable and more rapidly proteasome degraded. Transfection of S21 A/D eEF1A mutants in H1355 cells increased apoptosis in comparison with the wt isoforms. It indicates that the blockage of S21 interferes with or even supports C-Raf induced apoptosis rather than cell survival. Raf-mediated regulation of this site could be a crucial mechanism involved in the functional switching of eEF1A between its role in protein biosynthesis and its participation in other cellular processes.show moreshow less

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Metadaten
Author: C. Sanges, C. Scheuermann, R. P. Zahedi, A. Sickmann, A. Lamberti, N. Migliaccio, A. Baljuls, M. Marra, S. Zappavigna, J. Reinders, U. Rapp, A. Abbruzzese, M. Caraglia, P. Arcari
URN:urn:nbn:de:bvb:20-opus-124149
Document Type:Journal article
Faculties:Medizinische Fakultät / Institut für Medizinische Strahlenkunde und Zellforschung
Language:English
Parent Title (English):Cell Death and Disease
Year of Completion:2012
Volume:3
Issue:e276
Source:Cell Death and Disease (2012) 3, e276; doi:10.1038/cddis.2012.16
Source:Corrigendum: Cell Death and Disease (2012) 3, e317; doi:10.1038/cddis.2012.67
DOI:https://doi.org/10.1038/cddis.2012.16
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Tag:EF-1A; Raf kinases; apoptosis; mass spectrometry; signal transduction; ubiquitin
Release Date:2016/01/14
Licence (German):License LogoCC BY-NC-ND: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell, Keine Bearbeitung