Affinage

EIF4ENIF1

Eukaryotic translation initiation factor 4E transporter · UniProt Q9NRA8

Length
985 aa
Mass
108.2 kDa
Annotated
2026-06-09
22 papers in source corpus 18 papers cited in narrative 18 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/7 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

EIF4ENIF1 (4E-T) is a translational repressor and mRNA-fate regulator that bridges 5' cap recognition to the 3' decay and storage machinery, partitioning bound transcripts into a silenced rather than degraded state (PMID:26027925, PMID:32354837). It was first defined as a nucleocytoplasmic shuttling protein that mediates piggyback nuclear import of eIF4E via the importin αβ pathway, carrying a bipartite nuclear localization signal and leucine-rich export signals (PMID:10856257). In the cytoplasm 4E-T concentrates in P-bodies, where its eIF4E interaction represses translation and controls mRNA half-life (PMID:16157702). Mechanistically, 4E-T scaffolds a repressive ribonucleoprotein network: it binds the 5' cap through eIF4E (and the related 4EHP), engages the DEAD-box helicase DDX6 through its CUP-homology domain in a manner that uniquely tolerates simultaneous CNOT1 binding, and contacts LSM14A, the LSM1-7–PAT1B complex, UNR, and CNOT4 (PMID:26489469, PMID:26027925, PMID:27342281). Through sites in its middle region it recruits the CCR4-NOT deadenylase to promote deadenylation while its cap-binding interactions inhibit decapping and degradation, thereby storing transcripts in a deadenylated, repressed form (PMID:32354837). 4E-T can silence tethered mRNAs independently of its eIF4E-binding motif and independently of P-body localization, whereas global translational repression and miRNA-mediated decay require eIF4E binding (PMID:24335285, PMID:26027925). Its activity is tuned post-translationally: JNK phosphorylates six proline-directed sites under oxidative stress to drive P-body enlargement and complex assembly (PMID:22966201), TRIM56 and OTUD4 write and erase ubiquitin to control P-body formation (PMID:35830814), and a redox-sensitive intramolecular disulphide bond lowers eIF4E affinity ~300-fold (PMID:37798395). Biologically, 4E-T sequesters proneurogenic bHLH and transcription-regulator mRNAs in neural precursors to balance self-renewal against differentiation, with its loss causing premature neurogenesis (PMID:25456498, PMID:36924490), and it maintains oocyte prophase-I arrest by repressing meiotic drivers c-Mos and cyclin-B1 (PMID:40877279).

Mechanistic history

Synthesis pass · year-by-year structured walk · 17 steps
  1. 2000 High

    Established the founding molecular role of 4E-T: how the cap-binding protein eIF4E reaches the nucleus, by showing 4E-T is an eIF4E-dependent nuclear import adaptor.

    Evidence Co-IP, eIF4E-binding-deficient mutants, leptomycin B and nuclear accumulation assays

    PMID:10856257

    Open questions at the time
    • Did not address cytoplasmic translational functions
    • Functional consequence of eIF4E nuclear import on gene expression not defined
  2. 2005 High

    Reframed 4E-T as a cytoplasmic mRNA-fate regulator by placing it in P-bodies and linking its eIF4E interaction to translational repression and mRNA stability control.

    Evidence siRNA knockdown with mRNA stability assay, fluorescence co-localization, Co-IP

    PMID:16157702

    Open questions at the time
    • Did not resolve whether 4E-T promotes or protects against decay
    • Repressive partners beyond eIF4E not yet identified
  3. 2007 High

    Showed the repressive complex is context-specific, identifying an oocyte 4E-T network with CPEB, Xp54, Pat1, RAP55 and the oocyte-specific eIF4E1b, with cap-dependent repression not requiring the canonical eIF4E-binding motif.

    Evidence Co-IP, gel filtration, pull-downs and tether assays in Xenopus oocytes

    PMID:17942399

    Open questions at the time
    • Mechanism of motif-independent eIF4E1b binding undefined
    • Direct vs. indirect nature of several interactions not resolved
  4. 2012 High

    Identified stress-responsive regulation of 4E-T, defining JNK phosphorylation of six proline-directed sites as a switch for complex assembly and P-body enlargement.

    Evidence Quantitative MS, kinase assay, image-based P-body quantification, polysome profiling, siRNA

    PMID:22966201

    Open questions at the time
    • Which target mRNAs are affected by phosphorylation not mapped
    • Phosphorylation shown not to alter global translation, leaving the functional output narrow
  5. 2013 High

    Dissected the two modes of repression, showing tethered-mRNA silencing is eIF4E-independent and P-body-independent while global repression and miRNA silencing relief require eIF4E binding.

    Evidence Tether assay, polysome analysis, eIF4E-binding-motif mutagenesis, qPCR, northern blot

    PMID:24335285

    Open questions at the time
    • Effector mediating eIF4E-independent repression not identified
    • Endogenous target set not defined
  6. 2014 High

    Assigned an in vivo developmental function, showing a 4E-T–eIF4E1 complex sequesters proneurogenic bHLH mRNAs to maintain neural precursors.

    Evidence Co-IP, RNA-IP, shRNA/siRNA with neurogenesis phenotype, granule co-localization

    PMID:25456498

    Open questions at the time
    • Mechanism of mRNA selectivity unclear
    • Reversibility/derepression trigger during normal differentiation not defined
  7. 2015 High

    Resolved at atomic resolution how 4E-T engages the decay machinery, showing its CUP-homology domain wraps DDX6 and contacts CNOT1, uniquely retaining DDX6 binding when CNOT1 is engaged.

    Evidence 2.1 Å X-ray crystallography, in vitro binding, Co-IP

    PMID:26489469

    Open questions at the time
    • Functional consequence of simultaneous DDX6/CNOT1 engagement on individual mRNAs not measured
    • Structure of full repressive assembly unresolved
  8. 2015 High

    Defined 4E-T as a cap-to-decay bridge, mapping interactions with eIF4E, DDX6, LSM14 and LSM1-7–PAT1 and showing eIF4E binding is required for decay of miRNA targets.

    Evidence Co-IP, MS interactome, tether and mRNA decay assays, mutagenesis

    PMID:26027925

    Open questions at the time
    • Why some 4E-T activities favor decay while others favor storage not reconciled here
  9. 2015 High

    Placed 4E-T epistatically downstream of CCR4-NOT, establishing a CAF1–CCR4-NOT–Xp54–4E-T repression chain dependent on eIF4E binding.

    Evidence Tether/epistasis assays in Xenopus oocytes, AP-MS, Co-IP, truncation/mutation analysis

    PMID:26015597

    Open questions at the time
    • Generality of the chain order outside oocytes not tested
  10. 2015 Medium

    Linked 4E-T to stress survival, showing phosphomimetic eIF4E requires 4E-T binding to confer resistance to oxidative and DNA-damaging stress.

    Evidence Phosphomimetic/phospho-dead eIF4E expression, 4E-T knockdown, eIF4E-W73A mutagenesis, viability and polysome assays

    PMID:25923732

    Open questions at the time
    • Single lab; downstream survival effectors not identified
    • Mechanistic link between 4E-T binding and stress resistance unresolved
  11. 2016 High

    Comprehensively mapped the 4E-T interactome to distinct motifs, showing UNR and DDX6 binding sites cooperatively mediate repression and DDX6 binding drives de novo P-body assembly.

    Evidence MS, western blot, tether assay, deletion mutagenesis, miRNA reporter and P-body assays

    PMID:27342281

    Open questions at the time
    • Stoichiometry and order of assembly of the multi-partner complex not defined
  12. 2020 High

    Reconciled the storage-versus-decay paradox, showing 4E-T promotes deadenylation via middle-region CCR4-NOT recruitment while cap-binding interactions inhibit decapping, storing mRNAs in a deadenylated repressed state.

    Evidence Tether assay, CCR4-NOT site mutagenesis, mRNA decay assay, Co-IP, overexpression

    PMID:32354837

    Open questions at the time
    • Signals that convert stored mRNAs to degradation or reactivation not defined
    • In vivo relevance of the storage state across tissues untested here
  13. 2022 Medium

    Identified ubiquitin as a regulatory layer, with TRIM56 (writer) and OTUD4 (eraser) tuning 4E-T ubiquitination to control P-body assembly and neural progenitor cell-cycle progression.

    Evidence DUB/E3 identification, ubiquitination assays, OTUD4/TRIM56 manipulation, P-body and differentiation assays

    PMID:35830814

    Open questions at the time
    • Ubiquitinated residues and chain type not defined
    • Single lab; link between ubiquitination and specific mRNA fate not established
  14. 2023 Medium

    Defined a redox switch on 4E-T, showing an intramolecular disulphide between the 4E-binding motifs reduces eIF4E affinity ~300-fold.

    Evidence Biophysical binding under non-reducing conditions, mutagenesis, affinity measurement

    PMID:37798395

    Open questions at the time
    • In vitro only; cellular evidence that the disulphide forms under physiological oxidation lacking
    • Functional consequence for mRNA fate not tested
  15. 2023 High

    Extended the neural role transcriptome-wide and in vivo, showing 4E-T associates with ribosome-depleted transcription-regulator mRNAs and is required for NPC maintenance versus differentiation.

    Evidence RNA-IP, ribosome profiling, conditional KO and shRNA, in vivo neurogenesis phenotype

    PMID:36924490

    Open questions at the time
    • Selectivity determinants for bound mRNAs not defined
    • Coupling to specific decay/storage outcomes per transcript unresolved
  16. 2024 Medium

    Connected 4E-T to human fertility disease, showing wild-type represses global translation while POI-associated mutants (Q842P, R208H) fail to repress and derepress fertility-associated transcripts.

    Evidence T&T-seq dual-omics with WT and mutant overexpression in 293FT cells

    PMID:38604507

    Open questions at the time
    • Heterologous 293FT system, not oocytes
    • Causal link between specific derepressed transcripts and disease phenotype not established
  17. 2025 High

    Established 4E-T as essential for oocyte prophase-I arrest, showing acute loss triggers meiotic resumption via untimely c-Mos and cyclin-B1 translation, dependent on eIF4E and PATL2 binding.

    Evidence TRIM-Away acute depletion, western blot, meiotic maturation assays in mouse and Xenopus, Co-IP, mutagenesis

    PMID:40877279

    Open questions at the time
    • Full set of arrest-maintaining target mRNAs not defined
    • How fertilization/maturation signals relieve 4E-T repression unresolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • How the multiple regulatory inputs (JNK phosphorylation, TRIM56/OTUD4 ubiquitination, redox disulphide) are integrated to choose between mRNA storage, decay, and reactivation in a tissue-specific manner remains unresolved.
  • No unified model linking the regulatory modifications to specific mRNA-fate outcomes
  • Determinants of 4E-T target mRNA selectivity unknown
  • Reactivation/derepression triggers across cell types undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0045182 translation regulator activity 6 GO:0060090 molecular adaptor activity 4 GO:0140313 molecular sequestering activity 3 GO:0098772 molecular function regulator activity 2
Localization
GO:0005829 cytosol 3 GO:0005634 nucleus 1
Pathway
R-HSA-8953854 Metabolism of RNA 3 R-HSA-1266738 Developmental Biology 2 R-HSA-1474165 Reproduction 1
Partners
CNOT1CNOT4DDX6EIF4EEIF4E1BLSM14APATL2UNR
Complex memberships
4E-T–eIF4E repressive complexCCR4-NOT (recruited)LSM1-7–PAT1 complex (associated)P-body

Evidence

Reading pass · 18 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 4E-T mediates nuclear import of eIF4E via the importin αβ pathway by a piggyback mechanism; 4E-T contains a bipartite nuclear localization signal and two leucine-rich nuclear export signals, and eIF4E forms a complex with the importin αβ heterodimer only in the presence of 4E-T. Co-immunoprecipitation, overexpression of wild-type and eIF4E-binding-deficient mutant 4E-T, leptomycin B treatment, nuclear accumulation assay The EMBO journal High 10856257
2005 4E-T colocalizes with mRNA decapping factors in P-bodies and controls mRNA half-life; siRNA depletion of 4E-T increases mRNA stability, and 4E-T interaction with eIF4E represses translation, which is a prerequisite for targeting mRNAs to P-bodies. siRNA knockdown with mRNA stability assay, co-localization by fluorescence microscopy, co-immunoprecipitation The Journal of cell biology High 16157702
2005 Murine Clast4 (4E-T ortholog) is expressed in growing oocytes and undergoes phosphorylation upon meiotic maturation; direct interaction with eIF4E is mediated by a canonical and functional eIF4E-binding motif. Western blot, co-immunoprecipitation, phosphorylation assay, in situ hybridization Gene Medium 16343815
2007 In early Xenopus oocytes, 4E-T interacts with CPEB, the RNA helicase Xp54, RNA-binding proteins P100(Pat1) and RAP55, and the oocyte-specific eIF4E1b (not canonical eIF4E1a); 4E-T binding to eIF4E1b occurs independently of the consensus YSKEELL eIF4E-binding motif and represses translation in a cap-dependent manner. Co-immunoprecipitation, gel filtration, pull-down assays, tether function assays in Xenopus oocytes, antibody injection The Journal of biological chemistry High 17942399
2012 JNK phosphorylates 4E-T on six proline-directed sites in response to oxidative stress, and this phosphorylation is required for formation of the 4E-T complex and facilitates assembly of larger P-bodies under stress; 4E-T phosphorylation does not impact global translational control. Quantitative mass spectrometry, kinase assay, image-based computational P-body quantification, polysomal mRNA profiling, siRNA knockdown Molecular and cellular biology High 22966201
2013 4E-T represses translation of bound mRNAs in a tether-function assay independently of its eIF4E-binding site (YX4L) and independently of P-body localization; global translational repression requires eIF4E binding; depletion of 4E-T from HeLa cells increases steady-state translation and relieves microRNA-mediated silencing. Tether function assay, siRNA knockdown with polysome analysis, mutagenesis of eIF4E-binding motif, qPCR, northern blot Nucleic acids research High 24335285
2014 In embryonic cortical neural precursors, 4E-T forms a repressive complex with eIF4E1 that sequesters and represses translation of proneurogenic bHLH mRNAs; disruption of this complex causes premature neurogenesis and neural precursor depletion. Co-immunoprecipitation, RNA-immunoprecipitation, knockdown by shRNA/siRNA with neurogenesis phenotype readout, co-localization with Lsm1 and Rck in granules Neuron High 25456498
2015 4E-T interacts with DDX6 via its CUP-homology domain (CHD), which wraps around the RecA2 domain of DDX6 and contacts CNOT1; the crystal structure (2.1 Å) reveals that 4E-T CHD shares the same DDX6-binding surface as Edc3 and Pat1 FDF motifs, but unlike Edc3/Pat1, 4E-T CHD maintains DDX6 binding even upon CNOT1 MIF4G domain binding. X-ray crystallography at 2.1 Å, in vitro binding assay, co-immunoprecipitation Cell reports High 26489469
2015 4E-T bridges the 5' cap (via eIF4E binding) and 3' mRNA decay machinery (via interactions with DDX6, LSM14, and LSM1-7-PAT1 complex) to promote mRNA decay; 4E-T must interact with eIF4E to engender mRNA decay of microRNA targets. Co-immunoprecipitation, mass spectrometry, tether function assay, mRNA decay assay, mutagenesis Cell reports High 26027925
2015 In Xenopus oocytes, 4E-T acts downstream of NOT1 in a CAF1–CCR4-NOT–Xp54–4E-T repression chain; a 4E-T truncation that still binds eIF4E alleviates repression by tethered CAF1, NOT1, and Xp54, while a mutant 4E-T failing to bind eIF4E does not, indicating eIF4E-dependent activity is required for this repression axis. Tether function assay in Xenopus oocytes, affinity purification-mass spectrometry, co-immunoprecipitation, 4E-T truncation/mutation analysis RNA (New York, N.Y.) High 26015597
2015 Phosphomimetic eIF4E (S209D) requires direct interaction with 4E-T to confer resistance to oxidative stress and DNA-damaging agents; knockdown of 4E-T or use of an eIF4E-W73A-S209D mutant unable to bind 4E-T abolishes the stress resistance phenotype. Retroviral expression of phosphomimetic/phospho-dead eIF4E mutants, 4E-T siRNA knockdown, eIF4E-W73A mutagenesis, cell viability assay, polysome analysis PloS one Medium 25923732
2016 4E-T interacts with DDX6, UNR, unrip, PAT1B, LSM14A, and CNOT4 via distinct sites identified by mass spectrometry; joint deletion of two short conserved motifs binding UNR and DDX6 relieves translational repression; the DDX6–4E-T interaction mediates both miRNA-dependent translational repression and de novo P-body assembly. Mass spectrometry, western blotting, tether function assay, deletion mutagenesis, miRNA reporter assay, P-body assembly assay Nucleic acids research High 27342281
2020 4E-T promotes deadenylation of bound mRNAs via recruitment of the CCR4-NOT complex through previously uncharacterized sites in its middle region, while simultaneously inhibiting mRNA decapping and degradation through its interaction with cap-binding proteins eIF4E/4EHP, thereby storing mRNAs in a deadenylated, repressed form. Tether function assay, mutagenesis of CCR4-NOT interaction sites, mRNA decay assay, co-immunoprecipitation, 4E-T overexpression Genes & development High 32354837
2022 The deubiquitinase OTUD4 and E3 ubiquitin ligase TRIM56 counter-regulate the ubiquitination status of 4E-T to control P-body assembly in neural progenitor cells; aberrant 4E-T ubiquitination promotes P-body assembly and delays cell cycle progression, while loss of 4E-T ubiquitination abrogates P-bodies and causes premature neurogenesis. Deubiquitinase/E3-ligase identification, ubiquitination assay, genetic manipulation of OTUD4 and TRIM56, P-body quantification, neural progenitor differentiation assay Cell reports Medium 35830814
2023 An intramolecular disulphide bond between two cysteines located between the 4E-binding motifs of human 4E-T reduces its affinity for eIF4E1a by approximately 300-fold, functioning as a redox-sensitive switch regulating the 4E-T–eIF4E interaction. Biophysical binding assay under non-reducing conditions, mutagenesis, affinity measurement European biophysics journal : EBJ Medium 37798395
2023 In early postnatal forebrain NPCs, 4E-T broadly associates with mRNAs encoding transcriptional regulators that are depleted from ribosomes; 4E-T knockdown or conditional knockout derepresses proneurogenic mRNA translation and perturbs NPC maintenance vs. differentiation in vivo. RNA-immunoprecipitation, ribosome profiling, conditional knockout, shRNA knockdown, in vivo neurogenesis phenotype assay Cell reports High 36924490
2024 Overexpression of EIF4ENIF1 wild-type significantly reduces global translation efficiency; a POI-associated mutant Q842P fails to repress global translation, while R208H has a reduced inhibitory effect on high-TE genes; several fertility-associated genes (AMH, SERPINE1, THBS1) are translationally upregulated in mutant groups versus wild-type. T&T-seq (translation-transcription dual-omics sequencing), overexpression of WT and mutant EIF4ENIF1 in 293FT cells Gene Medium 38604507
2025 4E-T is required to maintain prophase-I arrest in mouse and frog oocytes; acute loss of 4E-T (via TRIM-Away) causes spontaneous meiotic resumption due to untimely translation of c-Mos and cyclin-B1; 4E-T association with eIF4E and PATL2 is critical for target mRNA binding and repression; a POI-associated 4E-T mutant fails to maintain prophase-I arrest in Xenopus oocytes. TRIM-Away acute protein depletion, western blot for c-Mos and cyclin-B1, meiotic maturation assay in mouse and Xenopus oocytes, co-immunoprecipitation of 4E-T with eIF4E and PATL2, mutagenesis Nature communications High 40877279

Source papers

Stage 0 corpus · 22 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 A role for the eIF4E-binding protein 4E-T in P-body formation and mRNA decay. The Journal of cell biology 204 16157702
2000 A novel shuttling protein, 4E-T, mediates the nuclear import of the mRNA 5' cap-binding protein, eIF4E. The EMBO journal 165 10856257
2007 CPEB interacts with an ovary-specific eIF4E and 4E-T in early Xenopus oocytes. The Journal of biological chemistry 151 17942399
2016 The DDX6-4E-T interaction mediates translational repression and P-body assembly. Nucleic acids research 104 27342281
2015 Structure of a Human 4E-T/DDX6/CNOT1 Complex Reveals the Different Interplay of DDX6-Binding Proteins with the CCR4-NOT Complex. Cell reports 90 26489469
2014 An eIF4E1/4E-T complex determines the genesis of neurons from precursors by translationally repressing a proneurogenic transcription program. Neuron 80 25456498
2013 Human 4E-T represses translation of bound mRNAs and enhances microRNA-mediated silencing. Nucleic acids research 70 24335285
2015 The eIF4E-Binding Protein 4E-T Is a Component of the mRNA Decay Machinery that Bridges the 5' and 3' Termini of Target mRNAs. Cell reports 69 26027925
2013 Mutations in eIF4ENIF1 are associated with primary ovarian insufficiency. The Journal of clinical endocrinology and metabolism 53 23902945
2020 4E-T-bound mRNAs are stored in a silenced and deadenylated form. Genes & development 41 32354837
2015 Phosphorylation of eIF4E Confers Resistance to Cellular Stress and DNA-Damaging Agents through an Interaction with 4E-T: A Rationale for Novel Therapeutic Approaches. PloS one 38 25923732
2019 A novel EIF4ENIF1 mutation associated with a diminished ovarian reserve and premature ovarian insufficiency identified by whole-exome sequencing. Journal of ovarian research 35 31810472
2012 Phosphorylation of the eukaryotic translation initiation factor 4E-transporter (4E-T) by c-Jun N-terminal kinase promotes stress-dependent P-body assembly. Molecular and cellular biology 30 22966201
2005 Clast4, the murine homologue of human eIF4E-Transporter, is highly expressed in developing oocytes and post-translationally modified at meiotic maturation. Gene 27 16343815
2015 Xenopus CAF1 requires NOT1-mediated interaction with 4E-T to repress translation in vivo. RNA (New York, N.Y.) 25 26015597
2022 Ubiquitination and deubiquitination of 4E-T regulate neural progenitor cell maintenance and neurogenesis by controlling P-body formation. Cell reports 11 35830814
2022 EIF4ENIF1 variants in two patients with non-syndromic premature ovarian insufficiency. European journal of medical genetics 10 36030004
2023 The P-body protein 4E-T represses translation to regulate the balance between cell genesis and establishment of the postnatal NSC pool. Cell reports 6 36924490
2021 Loss-of-function of Nicotiana tabacum L. eukaryotic translation initiation factors eIF4E1-S and eIF(iso)4E-T synergistically confers high-level resistance to both Potato virus Y (PVY) and resistance-breaking PVY. Breeding science 5 34377067
2024 POI-associated EIF4ENIF1 mutations exhibit impaired translation regulation abilities. Gene 4 38604507
2025 Translational repression by 4E-T is crucial to maintain the prophase-I arrest in vertebrate oocytes. Nature communications 2 40877279
2023 An intramolecular disulphide bond in human 4E-T affects its binding to eIF4E1a protein. European biophysics journal : EBJ 1 37798395

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