title: Components of the translational machinery are associated with juvenile glycine receptors and are redistributed to the cytoskeleton upon aging and synaptic activity.
abstract: The translation eukaryotic elongation factor 1alpha (eEF1A) is a monomeric GTPase involved in protein synthesis. In addition, this protein is thought to participate in other cellular functions such as actin bundling, cell cycle regulation, and apoptosis. Here we show that eEF1A is associated with the alpha2 subunit of the inhibitory glycine receptor in pulldown experiments with rat brain extracts. Moreover, additional proteins involved in translation like ribosomal S6 protein and p70 ribosomal S6 protein kinase as well as ERK1/2 and calcineurin were identified in the same pulldown approaches. Glycine receptor activation in spinal cord neurons cultured for 1 week resulted in an increased phosphorylation of ribosomal S6 protein. Immunocytochemistry showed that eEF1A and ribosomal S6 protein are localized in the soma, dendrites, and at synapses of cultured hippocampal and spinal cord neurons. Consistent with our biochemical data, immunoreactivities of both proteins were partially overlapping with glycine receptor immunoreactivity in cultured spinal cord and hippocampal neurons. After 5 weeks in culture, eEF1A immunoreactivity was redistributed to the cytoskeleton in about 45% of neurons. Interestingly, the degree of redistribution could be increased at earlier stages of in vitro differentiation by inhibition of either the ERK1/2 pathway or glycine receptors and simultaneous N-methyl-D-aspartate receptor activation. Our findings suggest a functional coupling of eEF1A with both inhibitory and excitatory receptors, possibly involving the ERK-signaling pathway.
authors.affiliation: Department of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany.
authors.forename: Raphael
authors.initials: R
authors.lastname: Bluem
authors.forename: Enrico
authors.initials: E
authors.lastname: Schmidt
authors.forename: Carsten
authors.initials: C
authors.lastname: Corvey
authors.forename: Michael
authors.initials: M
authors.lastname: Karas
authors.forename: Andrea
authors.initials: A
authors.lastname: Schlicksupp
authors.forename: Joachim
authors.initials: J
authors.lastname: Kirsch
authors.forename: Jochen
authors.initials: J
authors.lastname: Kuhse
mesh_terms: D000818:Animals; D003599:Cytoskeleton / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D009474:Neurons / Q000378:metabolism; D020648:Peptide Elongation Factor 1 / Q000096:biosynthesis / Q000502:physiology*; D014176:Protein Biosynthesis; D051381:Rats; D017208:Rats, Wistar; D018009:Receptors, Glycine / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D015398:Signal Transduction; D013116:Spinal Cord / Q000378:metabolism; D013569:Synapses
chemical_list: C503236:Eef1a2 protein, rat; D020648:Peptide Elongation Factor 1; D018009:Receptors, Glycine; D016194:Receptors, N-Methyl-D-Aspartate; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D048049:Extracellular Signal-Regulated MAP Kinases; D005998:Glycine