The elongation factor eEF1A2 controls translation and actin dynamics in dendritic spines

Synaptic plasticity involves structural modifications in dendritic spines that are modulated by local protein synthesis and actin remodeling. Here, we investigated the molecular mechanisms that connect synaptic stimulation to these processes. We found that the phosphorylation of isoform-specific sites in eEF1A2—an essential translation elongation factor in neurons—is a key modulator of structural plasticity in dendritic spines. Expression of a nonphosphorylatable eEF1A2 mutant stimulated mRNA translation but reduced actin dynamics and spine density. By contrast, a phosphomimetic eEF1A2 mutant exhibited decreased association with F-actin and was inactive as a translation elongation factor. Activation of metabotropic glutamate receptor signaling triggered transient dissociation of eEF1A2 from its regulatory guanine exchange factor (GEF) protein in dendritic spines in a phosphorylation-dependent manner. We propose that eEF1A2 establishes a cross-talk mechanism that coordinates translation and actin dynamics during spine remodeling.

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eEF1A2 controls local translation and actin dynamics in structural synaptic plasticity

10.1101/2020.10.20.346858 ◽

2020 ◽

Author(s):

Mònica B. Mendoza ◽

Sara Gutierrez ◽

Raúl Ortiz ◽

David F. Moreno ◽

Maria Dermit ◽

...

Keyword(s):

Synaptic Plasticity ◽

Dendritic Spines ◽

Metabotropic Glutamate Receptor ◽

Elongation Factor ◽

Structural Plasticity ◽

Actin Dynamics ◽

Dependent Manner ◽

Local Translation ◽

Translation Elongation Factor ◽

Translation Elongation

AbstractSynaptic plasticity involves structural modifications in dendritic spines. Increasing evidence suggests that structural plasticity is modulated by local protein synthesis and actin remodeling in a synapsis-specific manner. However, the precise molecular mechanisms connecting synaptic stimulation to these processes in dendritic spines are still unclear. In the present study, we demonstrate that the configuration of phosphorylation sites in eEF1A2, an essential translation elongation factor in neurons, is a key modulator of structural plasticity in dendritic spines. A mutant that cannot be phosphorylated stimulates translation but reduces actin dynamics and spine density. By contrast, the phosphomimetic variant loosens its association with F-actin and becomes inactive as a translation elongation factor. Metabotropic glutamate receptor signaling triggers a transient dissociation of eEF1A2 from its GEF protein in dendritic spines, in a phospho-dependent manner. We propose that eEF1A2 establishes a crosstalk mechanism that coordinates local translation and actin dynamics during spine remodeling.

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Translation Elongation Factor 4 (LepA) Contributes to Tetracycline Susceptibility by Stalling Elongating Ribosomes

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02356-17 ◽

2018 ◽

Vol 62 (8) ◽

Cited By ~ 3

Author(s):

Bin Liu ◽

Chunlai Chen

Keyword(s):

Protein Synthesis ◽

Ribosome Biogenesis ◽

Molecular Mechanisms ◽

Elongation Factor ◽

Ribosome Profiling ◽

Translation Elongation Factor ◽

Translation Elongation ◽

Content Type ◽

Elongation Phase ◽

Profiling Analysis

ABSTRACTEven though elongation factor 4 (EF4) is the third most conserved protein in bacteria, its physiological functions remain largely unknown and its proposed molecular mechanisms are conflicting among previous studies. In the present study, we show that the growth of anEscherichia colistrain is more susceptible to tetracycline than its EF4 knockout strain. Consistent with previous studies, our results suggested that EF4 affects ribosome biogenesis when tetracycline is present. Through ribosome profiling analysis, we discovered that EF4 causes 1-nucleotide shifting of ribosomal footprints on mRNA when cells have been exposed to tetracycline. In addition, when tetracycline is present, EF4 inhibits the elongation of protein synthesis, which leads to the accumulation of ribosomes in the early segment of mRNA. Altogether, when cells are exposed to tetracycline, EF4 alters both ribosome biogenesis and the elongation phase of protein synthesis.

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Autophagy-competent mitochondrial translation elongation factor TUFM inhibits caspase-8-mediated apoptosis

Cell Death and Differentiation ◽

10.1038/s41418-021-00868-y ◽

2021 ◽

Author(s):

Chang-Yong Choi ◽

Mai Tram Vo ◽

John Nicholas ◽

Young Bong Choi

Keyword(s):

Molecular Mechanisms ◽

Mitochondrial Dynamics ◽

Elongation Factor ◽

Productive Infection ◽

Caspase 8 ◽

Translation Elongation Factor ◽

Mitochondrial Translation ◽

Translation Elongation ◽

Cell Functions ◽

Induced Apoptosis

AbstractMitochondria support multiple cell functions, but an accumulation of dysfunctional or excessive mitochondria is detrimental to cells. We previously demonstrated that a defect in the autophagic removal of mitochondria, termed mitophagy, leads to the acceleration of apoptosis induced by herpesvirus productive infection. However, the exact molecular mechanisms underlying activation of mitophagy and regulation of apoptosis remain poorly understood despite the identification of various mitophagy-associated proteins. Here, we report that the mitochondrial translation elongation factor Tu, a mitophagy-associated protein encoded by the TUFM gene, locates in part on the outer membrane of mitochondria (OMM) where it acts as an inhibitor of altered mitochondria-induced apoptosis through its autophagic function. Inducible depletion of TUFM potentiated caspase-8-mediated apoptosis in virus-infected cells with accumulation of altered mitochondria. In addition, TUFM depletion promoted caspase-8 activation induced by treatment with TNF-related apoptosis-inducing ligand in cancer cells, potentially via dysregulation of mitochondrial dynamics and mitophagy. Importantly, we revealed the existence of and structural requirements for autophagy-competent TUFM on the OMM; the GxxxG motif within the N-terminal mitochondrial targeting sequences of TUFM was required for self-dimerization and mitophagy. Furthermore, we found that autophagy-competent TUFM was subject to ubiquitin-proteasome-mediated degradation but stabilized upon mitophagy or autophagy activation. Moreover, overexpression of autophagy-competent TUFM could inhibit caspase-8 activation. These studies extend our knowledge of mitophagy regulation of apoptosis and could provide a novel strategic basis for targeted therapy of cancer and viral diseases.

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MicroRNA-33a-5p Modulates Japanese Encephalitis Virus Replication by Targeting Eukaryotic Translation Elongation Factor 1A1

Journal of Virology ◽

10.1128/jvi.03242-15 ◽

2016 ◽

Vol 90 (7) ◽

pp. 3722-3734 ◽

Cited By ~ 32

Author(s):

Zheng Chen ◽

Jing Ye ◽

Usama Ashraf ◽

Yunchuan Li ◽

Siqi Wei ◽

...

Keyword(s):

Viral Replication ◽

Molecular Mechanisms ◽

Elongation Factor ◽

Negative Regulator ◽

Translation Elongation Factor ◽

Cellular Mirnas ◽

Translation Elongation ◽

Eukaryotic Translation ◽

Acute Encephalitis ◽

Replicase Complex

ABSTRACTJapanese encephalitis virus (JEV) is a typical mosquito-borne flavivirus responsible for acute encephalitis and meningitis in humans. However, the molecular mechanism for JEV pathogenesis is still unclear. MicroRNAs (miRNAs) are small noncoding RNAs that act as gene regulators. They are directly or indirectly involved in many cellular functions owing to their ability to target mRNAs for degradation or translational repression. However, how cellular miRNAs are regulated and their functions during JEV infection are largely unknown. In the present study, we found that JEV infection downregulated the expression of endogenous cellular miR-33a-5p. Notably, artificially transfecting with miR-33a-5p mimics led to a significant decrease in viral replication, suggesting that miR-33a-5p acts as a negative regulator of JEV replication. A dual-luciferase reporter assay identified eukaryotic translation elongation factor 1A1 (EEF1A1) as one of the miR-33a-5p target genes. Our study further demonstrated thatEEF1A1can interact with the JEV proteins NS3 and NS5 in replicase complex. Through this interaction,EEF1A1can stabilize the components of viral replicase complex and thus facilitates viral replication during JEV infection. Taken together, these results suggest that miR-33a-5p is downregulated during JEV infection, which contributes to viral replication by increasing the intracellular level ofEEF1A1, an interaction partner of JEV NS3 and NS5. This study provides a better understanding of the molecular mechanisms of JEV pathogenesis.IMPORTANCEMiRNAs are critical regulators of gene expression that utilize sequence complementarity to bind to and modulate the stability or translation efficiency of target mRNAs. Accumulating data suggest that miRNAs regulate a wide variety of molecular mechanisms in the host cells during viral infections. JEV, a neurotropic flavivirus, is one of the major causes of acute encephalitis in humans worldwide. The roles of cellular miRNAs during JEV infections are widely unexplored. The present study explores a novel role of miR-33a-5p as a negative regulator of JEV replication. We foundEEF1A1as a direct target of miR-33a-5p. We also demonstrated thatEEF1A1interacts with and stabilize the components of JEV replicase complex, which positively regulates JEV replication. These findings suggest a new insight into the molecular mechanism of JEV pathogenesis and provide a possible therapeutic entry point for viral encephalitis.

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Changes in the Number and Morphology of Dendritic Spines in the Hippocampus and Prefrontal Cortex of the C58/J Mouse Model of Autism

Frontiers in Cellular Neuroscience ◽

10.3389/fncel.2021.726501 ◽

2021 ◽

Vol 15 ◽

Author(s):

Isabel Barón-Mendoza ◽

Emely Maqueda-Martínez ◽

Mónica Martínez-Marcial ◽

Marisol De la Fuente-Granada ◽

Margarita Gómez-Chavarin ◽

...

Keyword(s):

Prefrontal Cortex ◽

Dendritic Spines ◽

Metabotropic Glutamate Receptor ◽

Inbred Mouse ◽

Inbred Mouse Strain ◽

Stereotyped Behavior ◽

Autism Spectrum ◽

Dependent Manner ◽

Nucleotide Polymorphisms ◽

Spine Density

Autism spectrum disorder (ASD) has a broad range of neurobiological characteristics, including alterations in dendritic spines, where approximately 90% of excitatory synapses occur. Therefore, changes in their number or morphology would be related to atypical brain communication. The C58/J inbred mouse strain displays low sociability, impaired communication, and stereotyped behavior; hence, it is considered among the animal models suitable for the study of idiopathic autism. Thus, this study aimed to evaluate the dendritic spine differences in the hippocampus and the prefrontal cortex of C58/J mice. We found changes in the number of spines and morphology in a brain region-dependent manner: a subtle decrease in spine density in the prefrontal cortex, higher frequency of immature phenotype spines characterized by filopodia-like length or small morphology, and a lower number of mature phenotype spines with mushroom-like or wide heads in the hippocampus. Moreover, an in silico analysis showed single nucleotide polymorphisms (SNPs) at genes collectively involved in regulating structural plasticity with a likely association with ASD, including MAP1A (Microtubule-Associated Protein 1A), GRM7 (Metabotropic Glutamate Receptor, 7), ANKRD11 (Ankyrin Repeat Domain 11), and SLC6A4 (Solute Carrier Family 6, member 4), which might support the relationship between the C58/J strain genome, an autistic-like behavior, and the observed anomalies in the dendritic spines.

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Repression of eEF2K transcription by NF-κB tunes translation elongation to inflammation and dsDNA-sensing

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1909143116 ◽

2019 ◽

Vol 116 (45) ◽

pp. 22583-22590 ◽

Cited By ~ 3

Author(s):

Christopher Bianco ◽

Letitia Thompson ◽

Ian Mohr

Keyword(s):

Protein Synthesis ◽

Transcriptional Repression ◽

Elongation Factor ◽

Mrna Translation ◽

Bacterial Toxin ◽

Translation Elongation Factor ◽

Translation Elongation ◽

Protein Levels ◽

Cellular Translation ◽

Infection And Inflammation

Gene expression is rapidly remodeled by infection and inflammation in part via transcription factor NF-κB activation and regulated protein synthesis. While protein synthesis is largely controlled by mRNA translation initiation, whether cellular translation elongation factors are responsive to inflammation and infection remains poorly understood. Here, we reveal a surprising mechanism whereby NF-κB restricts phosphorylation of the critical translation elongation factor eEF2, which catalyzes the protein synthesis translocation step. Upon exposure to NF-κB–activating stimuli, including TNFα, human cytomegalovirus infection, or double-stranded DNA, eEF2 phosphorylation on Thr56, which slows elongation to limit protein synthesis, and the overall abundance of eEF2 kinase (eEF2K) are reduced. Significantly, this reflected a p65 NF-κB subunit-dependent reduction in eEF2K pre-mRNA, indicating that NF-κB activation represses eEF2K transcription to decrease eEF2K protein levels. Finally, we demonstrate that reducing eEF2K abundance regulates protein synthesis in response to a bacterial toxin that inactivates eEF2. This establishes that NF-κB activation by diverse physiological effectors controls eEF2 activity via a transcriptional repression mechanism that reduces eEF2K polypeptide abundance to preclude eEF2 phosphorylation, thereby stimulating translation elongation and protein synthesis. Moreover, it illustrates how nuclear transcription regulation shapes translation elongation factor activity and exposes how eEF2 is integrated into innate immune response networks orchestrated by NF-κB.

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