title: Brain-derived neurotrophic factor enhances the basal rate of protein synthesis by increasing active eukaryotic elongation factor 2 levels and promoting translation elongation in cortical neurons.
abstract: The constitutive and activity-dependent components of protein synthesis are both critical for neural function. Although the mechanisms controlling extracellularly induced protein synthesis are becoming clear, less is understood about the molecular networks that regulate the basal translation rate. Here we describe the effects of chronic treatment with various neurotrophic factors and cytokines on the basal rate of protein synthesis in primary cortical neurons. Among the examined factors, brain-derived neurotrophic factor (BDNF) showed the strongest effect. The rate of protein synthesis increased in the cortical tissues of BDNF transgenic mice, whereas it decreased in BDNF knock-out mice. BDNF specifically increased the level of the active, unphosphorylated form of eukaryotic elongation factor 2 (eEF2). The levels of active eEF2 increased and decreased in BDNF transgenic and BDNF knock-out mice, respectively. BDNF decreased kinase activity and increased phosphatase activity against eEF2 in vitro. Additionally, BDNF shortened the ribosomal transit time, an index of translation elongation. In agreement with these results, overexpression of eEF2 enhanced protein synthesis. Taken together, our results demonstrate that the increased level of active eEF2 induced by chronic BDNF stimulation enhances translational elongation processes and increases the total rate of protein synthesis in neurons.
authors.affiliation: Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan. nobtak@bri.niigata-u.ac.jp
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Takei
authors.forename: Mihoko
authors.initials: M
authors.lastname: Kawamura
authors.forename: Yuta
authors.initials: Y
authors.lastname: Ishizuka
authors.forename: Naomasa
authors.initials: N
authors.lastname: Kakiya
authors.forename: Naoko
authors.initials: N
authors.lastname: Inamura
authors.forename: Hisaaki
authors.initials: H
authors.lastname: Namba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nawa
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000494:pharmacology*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology; D016207:Cytokines / Q000494:pharmacology; D054736:Elongation Factor 2 Kinase / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009154:Mutation; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020652:Peptide Elongation Factor 2 / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012270:Ribosomes / Q000378:metabolism; D013997:Time Factors
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins; D020652:Peptide Elongation Factor 2; D054736:Elongation Factor 2 Kinase