Localization of Translation Initiation Factors to the Postsynaptic Sites

Choi, Myoung-Kwon; Park, Sung-Dong; Park, In-Sick; Moon, Il-Soo

doi:10.5352/jls.2011.21.11.1526

Cited by 2 publications

(3 citation statements)

References 31 publications

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“…For example, eEF1A were highly enriched at the postsynaptic sites ( 26 ). Translation initiation factors such as eIF4E and eIF4G (which bind the 5'-terminal mRNA cap), eIF5 (which is important during the 3' direction scanning to find an initiation codon), eIF6 (which mediates upregulation of translation by external stimuli), and eIF5A (which mediate translation upregulation under adverse conditions) were localized to the postsynaptic sites ( 16 ).…”

Section: Discussionmentioning

confidence: 99%

“…For example, eIF4E is mainly concentrated in the dendritic lipid raft in close proximity to the postsynaptic sites ( 14 ), and treatment of various neuronal preparations with the brain-derived neurotrophic factor results in redistribution of the eIF4E into dendritic spines ( 15 ). Other translation factors eIFs ( 16 ) and eEF1A ( 17 ) and are enriched in the postsynaptic sites.…”

Section: Introductionmentioning

confidence: 99%

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Dendritic eIF4E-binding Protein 1 (eIF4E-BP1) mRNA Is Upregulated by Neuronal Activation

2012

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Long-term synaptic plasticity requires addition of new proteins at the synaptic site. The local protein synthesis at subsynaptic sites confers advantageous mechanisms that would regulate the protein composition in local domains on a moment-by-moment basis. However, our information on the identities of 'dendritic' mRNAs is very limited. In this study we investigated the expression of the protein and mRNA for eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4EBP1) in cultured rat hippocampal neurons. Immunocytochemistry (ICC) showed that 4EBP1 protein is highly localized to the nucleus. In dendrites most 4EBP1 punctae were not colocalized with those of eIF4E. In situ hybridization (ISH) and Fluorescence ISH (FISH) revealed that 4EBP1 mRNA was present in dendrites. The FISH signals formed clusters along dendrites that colocalized with ICC signals for Staufen, a marker for RNA granules. The neuronal activation by KCl (60 mM, 10 min) significantly increased the density of 4EBP1 FISH signals in the nucleus after 2 hr, and both in the nucleus and dendrites after 6 hr. Our results indicate that 4EBP1 and its mRNA are present in dendrites, and the mRNA is upregulated and transported to dendritic domains in RNA granules upon neuronal activation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dendritic eIF4E-binding Protein 1 (eIF4E-BP1) mRNA Is Upregulated by Neuronal Activation

2012

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“…Immunocytochemistry (ICC) and western blotting also showed the postsynaptic localization of eIF4E, eIF4EBP1, eIF4EBP2 [16]. High resolution confocal microscopy and detergent extraction experiments showed that the eIF4E, eIF4G, eIF5, eIF5A and eIF6 were localized to the postsynaptic sites in association with the postsynaptic density (PSD) [3]. Furthermore, eIF4E and eIF4EBP1 mRNAs are localized, and upregulated by neuronal stimulation, in dendrites of cultured rat hippocampal neurons [9,11].…”

Section: Introductionmentioning

confidence: 97%

Developmental Expression of Eukaryotic Initiation Factor 4E (eIF4E) and eIF4E-binding Protein 1 (eIF4EBP1) in Rat Hippocampal Neurons

Park¹,

Moon²

2013

Journal of Life Science

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Local protein synthesis at subsynaptic sites plays a key role in the regulation of the protein composition in local domains. In this study, we carried out immunocytochemistry of cultured rat hippocampal neurons in various developmental stages to investigate the expression of eIF4E and its binding protein, eIF4EBP1. Both proteins were distributed in dendrites. In addition, eIF4EBP1 was highly expressed in the nucleus throughout the development, whereas eIF4E was not expressed in the nucleus. Punctate expression of eIF4E and eIF4EBP1 was evident in DIV 3. The colocalization rates of eIF4E or eIF4EBP1 puncta with PSD95 were higher in the dendrogenic than in the mature stages. In contrast, the colocalization rates of eIF4E and eIF4EBP1 puncta were higher in the mature than in the dendrogenic stages. As eIF4E is inactive when it is bound to eIF4EBP1, these data indicate that most dendritic eIF4E's are active during development but that they are mostly under inhibition in mature neurons.Key words : Development, eukaryotic translation initiation factor 4E (eIF4E), eIF4E-binding protein 1 (eIF4EBP1), hippocampal neuron, immunocytochemistry † Present address: Seoul Yonhap Clinic, 69-48 Namseok-Ri, YeongdeokEup, Yeongdeok-Gun, Gyeongsangbuk-Do 766-801, Korea *Corresponding author *Tel：+82-54-770-2414, Fax：+82-54-770-2447 *E-mail : moonis@dongguk.ac.kr This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. IntroductionFunctions of the brain are based on the neural networks which are dynamically remodeled by changes in the strength of synaptic connections. The long-lasting changes in synaptic strength, such as long-term potentiation (LTP), require new protein synthesis [4,8,13]. The local protein synthesis at subsynaptic sites plays a key advantageous mechanism that would regulate the protein composition in local domains on a moment-by-moment basis. In the translation process of protein synthesis, initiation is the rate limiting step where most of translational control occurs [14]. During translation initiation, eukaryotic translation initiation factor 4E (eIF4E) binds the 5'-cap structure of mRNA and the ribosome-associated scaffold protein eIF4G [17] in the cytoplasm. The eIF4E-binding protein 1 (eIF4EBP1) acts as a negative regulator of this process by preventing interaction of eIF4E with eIF4G in a competitive manner [7].In addition to the organelles such as rough endoplasmic reticulum and Golgi outpost that are necessary for protein synthesis, many translation factors were found located in the dendrite. Presence of eIF4E in postsynaptic region was revealed by electron microscopic study [1]. Immunocytochemistry (ICC) and western blotting also showed the postsynaptic localization of eIF4E, eIF4EBP1, eIF4EBP2 [16]. High resolution confocal microscopy and detergent extraction ...

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Localization of Translation Initiation Factors to the Postsynaptic Sites

Cited by 2 publications

References 31 publications

Dendritic eIF4E-binding Protein 1 (eIF4E-BP1) mRNA Is Upregulated by Neuronal Activation

Dendritic eIF4E-binding Protein 1 (eIF4E-BP1) mRNA Is Upregulated by Neuronal Activation

Developmental Expression of Eukaryotic Initiation Factor 4E (eIF4E) and eIF4E-binding Protein 1 (eIF4EBP1) in Rat Hippocampal Neurons

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