title: Upstream Open Reading Frames Located in the Leader of Protein Kinase Mζ mRNA Regulate Its Translation.
abstract: For protein synthesis that occurs locally in dendrites, the translational control mechanisms are much more important for neuronal functioning than the transcription levels. Here, we show that uORFs (upstream open reading frames) in the 5' untranslated region (5'UTR) play a critical role in regulation of the translation of protein kinase Mζ (PKMζ). Elimination of these uORFs activates translation of the reporter proteinin vitroand in primary cultures of rat hippocampal neurons. Using cell-free translation systems, we demonstrate that translational initiation complexes are formed only on uORFs. Further, we address the mechanism of translational repression of PKMζ translation, by uORFs. We observed an increase in translation of the reporter protein under the control of PKMζ leader in neuronal culture during non-specific activation by picrotoxin. We also show that such a mechanism is similar to the mechanism seen in cell stress, as application of sodium arsenite to neuron cultures induced translation of mRNA carrying PKMζ 5'UTR similarly to picrotoxin activation. Therefore, we suppose that phosphorylation of eIF2a, like in cell stress, is a main regulator of PKMζ translation. Altogether, our findings considerably extend our understanding of the role of uORF in regulation of PKMζ translation in activated neurons, important at early stages of LTP.
authors: Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia.
authors: Natalia V
authors: NV
authors: Bal
authors: Laboratory of Mechanisms and Control of Translation, Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia; Faculty of Bioengineering and Bioinformatics, M. V. Lomonosov Moscow State UniversityMoscow, Russia.
authors: Denis
authors: D
authors: Susorov
authors: Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia.
authors: Ekaterina
authors: E
authors: Chesnokova
authors: Laboratory of System Biology and Computational Genetics, Vavilov Institute of General Genetics, Russian Academy of Sciences Moscow, Russia.
authors: Artem
authors: A
authors: Kasianov
authors: Laboratory of Mechanisms and Control of Translation, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences Moscow, Russia.
authors: Tatiana
authors: T
authors: Mikhailova
authors: Laboratory of Mechanisms and Control of Translation, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences Moscow, Russia.
authors: Elena
authors: E
authors: Alkalaeva
authors: Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia.
authors: Pavel M
authors: PM
authors: Balaban
authors: Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia.
authors: Peter
authors: P
authors: Kolosov
keywords: PKMζ; eIF2a phosphorylation; local protein synthesis; translational control; uORF