| 1997 |
MNK1 (Mnk1) binds tightly to ERK1/ERK2 and p38 MAP kinases; ERK and p38 phosphorylate and activate MNK1, which then phosphorylates eIF4E at Ser209 in vitro. MNK1 complexes more strongly with inactive than active Erk, suggesting dissociation after mitogen stimulation. Mitogen- and stress-mediated MNK1 activation is blocked by MEK1 and p38 inhibitors. |
In vitro kinase assays, co-immunoprecipitation, dominant-negative/activated mutant expression, pharmacological inhibition |
The EMBO journal |
High |
9155017
|
| 1997 |
MNK1 is phosphorylated and activated in vitro by ERK1 and p38 MAP kinases but not by JNK/SAPK. Activation is differentially blocked by MEK inhibitor PD098059 or p38 inhibitor SB202190 in cells, placing MNK1 downstream of both ERK and p38 signaling branches. |
In vitro phosphorylation screening (solid-phase expression library), in vitro kinase assay, pharmacological inhibition in HeLa cells |
The EMBO journal |
High |
9155018
|
| 1999 |
MNK1 is recruited to the eIF4F complex via direct interaction with the C-terminal region of eIF4G, enabling phosphorylation of eIF4E at Ser209. An eIF4E mutant lacking eIF4G-binding capability shows severely impaired phosphorylation in cells. MNK1 also interacts with the C-terminal region of p97 (an eIF4G-related protein), which may block eIF4E phosphorylation by sequestering MNK1. |
Co-immunoprecipitation, mutant eIF4E expression in cells, in vitro binding assays |
The EMBO journal |
High |
9878069
|
| 1999 |
MNK1 binds directly to eIF4G and co-purifies with eIF4G and eIF4E in vivo. Dominant-negative MNK1 reduces mitogen-induced eIF4E phosphorylation; activated MNK1 increases basal eIF4E phosphorylation and can phosphorylate eIF4E even when 4EBP1 is overexpressed, establishing MNK1 as the cellular eIF4E kinase acting independently of 4EBP1 release. |
Co-purification, dominant-negative and activated mutant expression, in vivo phosphorylation assays |
Molecular and cellular biology |
High |
10022874
|
| 2000 |
MNK1 phosphorylates cytosolic phospholipase A2 (cPLA2) in vitro uniquely on Ser-727 (identified by mass spectrometry). Expression of dominant-negative MNK1 in HEK293 cells significantly inhibits cPLA2-mediated arachidonate release, identifying cPLA2 as a physiological substrate of MNK1. |
In vitro kinase assay, mass spectrometry, dominant-negative MNK1 expression, arachidonate release assay |
The Journal of biological chemistry |
High |
10978317
|
| 2000 |
Adenovirus inhibits cellular mRNA translation by displacing MNK1 from eIF4G via the viral 100K protein, which binds the C-terminus of eIF4G in vivo and in vitro at the same site as MNK1, thereby blocking eIF4E phosphorylation. Purified 100K protein evicts MNK1 from isolated eIF4F complexes in vitro. |
Co-immunoprecipitation, in vitro competition assays with purified proteins, temperature-sensitive viral mutant analysis |
The EMBO journal |
High |
10880459
|
| 2004 |
Mnk1 and Mnk2 are the exclusive eIF4E kinases in fibroblasts and adult tissues. In Mnk1/Mnk2 double-knockout mice, eIF4E Ser209 is not phosphorylated even with ERK/p38 activation. Mnk1 is responsible for inducible eIF4E phosphorylation whereas Mnk2 mainly mediates constitutive/basal phosphorylation. Despite complete absence of phospho-eIF4E, general protein synthesis and cap-dependent translation are not affected. |
Genetic knockout (single and double KO mice), bicistronic reporter assay, LPS/insulin stimulation in vivo, embryonic fibroblast analysis |
Molecular and cellular biology |
High |
15254222
|
| 2004 |
eIF4G recruits MNK1 through a structural interaction at its C-terminal HEAT-repeat domain; the eIF4G-binding site on MNK1 resides in a polybasic N-terminal region that also interacts with importin-α. MNK1 contains a CRM1-type nuclear export signal in its C-terminus; mutations abolishing export cause nuclear accumulation. Mutations reducing MNK1-eIF4G binding in vivo and in vitro also decrease eIF4E phosphorylation. |
Mutagenesis, nuclear/cytoplasmic fractionation, co-immunoprecipitation, importin-α binding assay |
The Journal of biological chemistry |
High |
12949082
|
| 2004 |
The adenovirus 100K protein displaces MNK1 from eIF4G through a competitive binding mechanism; 100K protein and MNK1 share a common eIF4G-binding motif. Unlike MNK1, 100K binds eIF4G in an RNA-independent manner and with higher affinity, blocking cap-dependent cellular mRNA translation. |
Mutational analysis of 100K protein, in vitro competition binding assays, in vivo co-immunoprecipitation |
Journal of virology |
High |
15220445
|
| 2004 |
HSV-1 ICP0 stimulates eIF4E phosphorylation (and 4E-BP1 phosphorylation) in infected cells in an MNK1-dependent manner; 4E-BP1 is degraded by the proteasome in an ICP0-dependent manner. Pharmacological inhibition of MNK1 dramatically reduces HSV-1 replication and viral polypeptide translation in quiescent cells. |
MNK1 inhibitor treatment, ICP0 mutant virus, proteasome inhibitor, viral protein synthesis and replication assays |
Genes & development |
Medium |
15075293
|
| 2004 |
Caspase-activated Pak2/γ-PAK phosphorylates MNK1 at Thr22 and Ser27 (identified by tryptic phosphopeptide mapping and Edman degradation). This phosphorylation inhibits binding of eIF4G peptides to MNK1 by up to 80% and reduces MNK1-mediated phosphorylation of eIF4G (but not eIF4E) by up to 50%, suggesting a role for Pak2 in downregulating translation initiation during apoptosis. |
In vitro kinase assay, 2D tryptic phosphopeptide mapping, automated microsequencing, binding assays with eIF4G peptides, apoptosis induction in 293T cells |
The Journal of biological chemistry |
High |
15234964
|
| 2004 |
MNK1 splice variant Mnk1b lacks the C-terminal ERK1/2 binding site and is therefore not phosphorylated/activated by ERK1/2, yet retains the ability to phosphorylate eIF4E in vitro and in vivo in a MAPK-independent manner. Mnk1b localizes to the nucleus (retaining NLS but lacking NES), whereas Mnk1 is exclusively cytoplasmic. |
Molecular cloning, in vitro kinase assay, immunofluorescence/subcellular fractionation, site-specific deletion analysis |
Experimental cell research |
Medium |
15350534
|
| 2004 |
NMDA receptor activation in hippocampal CA1 results in PKA- and ERK-dependent activation of MNK1 and increased eIF4E phosphorylation. This signaling is present in synaptoneurosome preparations and occurs in dendrites, identifying a pathway coupling synaptic activity to local translation initiation. |
Hippocampal slice pharmacology (PKA, PKC, ERK inhibitors), MNK1 kinase activity assay, immunohistochemistry, synaptoneurosome fractionation |
Journal of neurochemistry |
Medium |
15447679
|
| 2005 |
The Drosophila MNK1/2 homolog Lk6 regulates growth via eIF4E in a diet-dependent manner; overexpression of Lk6 causes growth inhibition in an eIF4E-dependent manner (genetic epistasis). Loss of Lk6 causes growth reduction under low-protein diet conditions. |
Drosophila genetics (loss-of-function, overexpression, epistasis with eIF4E mutants), body size measurements under dietary variation |
Current biology |
Medium |
15649360
|
| 2005 |
Differences in basal activity and MAPK regulation between MNK1 and MNK2 are determined by features in both their catalytic domains and C-terminal MAPK-binding motifs. MNK2 (but not MNK1) can bind phosphorylated/active ERK, which protects ERK from dephosphorylation. An aspartate in MNK2's catalytic domain is essential for activity (Ala mutation inactivates MNK2). Association of MNKs with eIF4G is negatively modulated by MNK activity. |
Site-directed mutagenesis of catalytic domain and C-terminus, co-immunoprecipitation with ERK, kinase activity assays |
The Journal of biological chemistry |
Medium |
16162500
|
| 2006 |
MNK1 phosphorylates human Sprouty2 (hSpry2) on Ser112 and Ser121. This phosphorylation stabilizes hSpry2 by antagonizing tyrosine phosphorylation, thereby reducing c-Cbl binding and polyubiquitination-dependent degradation. Loss of MNK1-mediated serine phosphorylation enhances hSpry2 degradation and impairs its inhibition of FGF-induced ERK activation. |
In vitro kinase assay, site-directed mutagenesis of Spry2, pharmacological MNK1 inhibition, ubiquitination assay, ERK activation assay |
Molecular and cellular biology |
High |
16479008
|
| 2006 |
The X-ray crystal structure of the C-terminal HEAT-repeat domain of eIF4G (at 2.2 Å resolution) identifies two atypical HEAT domains; structure-guided mutagenesis maps the MNK1 binding site to two conserved aromatic/acidic-box (AA-box) motifs within the second HEAT domain. The acidic residues form a negatively charged surface interacting with basic residues in MNK1. |
X-ray crystallography (2.2 Å), structure-guided surface mutagenesis, protein-protein interaction assays |
Structure |
High |
16698552
|
| 2007 |
MNK1 is a key downstream effector of MEKs in regulating HDM2 mRNA nuclear export; eIF4E promotes HDM2 mRNA export in a MEK- and MNK1-dependent manner through sequences in the 3' UTR of HDM2 mRNA. This pathway regulates mRNAs from both the P1 and P2 HDM2 promoters. |
Pharmacological MNK1 inhibition, eIF4E overexpression, mRNA export assay, 3'UTR reporter assay in breast cancer cells |
Oncogene |
Medium |
17828301
|
| 2006 |
Inorganic phosphate (Pi) activates Mnk1 through an Akt-mediated MEK/ERK pathway and facilitates translocation of MNK1 from cytosol into nucleus, where it increases eIF4E-BP1 phosphorylation to stimulate cap-dependent protein translation. |
Subcellular fractionation, pharmacological pathway inhibition, phosphorylation assays in human bronchial epithelial cells |
American journal of respiratory cell and molecular biology |
Low |
16763222
|
| 2008 |
Arsenic trioxide activates MNK1 and MNK2 phosphorylation in a p38α-dependent manner. In cells with targeted disruption of Mnk1/Mnk2 genes, arsenic-induced apoptosis is enhanced, establishing that MNK1/2 act as negative-feedback regulators of arsenic-induced apoptosis. |
Genetic knockout cells (Mnk1-/-, Mnk2-/-, double KO), pharmacological p38 inhibition, phosphorylation assays, apoptosis assays |
The Journal of biological chemistry |
High |
18299328
|
| 2009 |
Type I IFNs induce phosphorylation/activation of MNK1, which requires upstream Jak1 and downstream MEK/ERK activation. MNK kinases are essential for mRNA translation of ISG15 and ISG54 genes in response to IFN. MNK kinase activity contributes to the growth inhibitory effects of type I IFNs on hematopoietic progenitors. |
Double Mnk1/Mnk2 KO MEFs, siRNA knockdown, pharmacological MNK inhibition, pathway inhibitors (Jak, MEK), mRNA translation assays |
PNAS |
High |
19574459
|
| 2010 |
MAPK-mediated phosphorylation of the MNK1 active site controls eIF4G binding. The C-terminal domain of MNK1 restricts eIF4G interaction, preventing eIF4E phosphorylation in the absence of MAPK signaling. MNK1 autoregulates its interaction with eIF4G, releasing itself from the scaffold after phosphorylating eIF4E (demonstrated using a kinase-dead mutant and small-molecule inhibitor). |
Co-immunoprecipitation, naturally occurring splice variant analysis, small-molecule MNK1 inhibitor, kinase-dead MNK1 mutant |
Molecular and cellular biology |
High |
20823271
|
| 2010 |
Loss of Mnk1/2 suppresses tumorigenesis in the Lck-Pten mouse lymphoma model; phospho-eIF4E is elevated in lymphomas of parental mice but absent in Mnk-DKO mice. Stable knockdown of MNK1 in U87MG glioma cells dramatically decreases tumor formation in athymic nude mice. |
Genetic double KO in cancer-prone mouse model, stable shRNA knockdown, xenograft tumor formation assay |
PNAS |
High |
20679220
|
| 2011 |
PKCα phosphorylates eIF4G1 at Ser1186, which modulates eIF4G1 interaction with MNK1; PKCα activation triggers a cascade of eIF4G phosphorylation events that control binding of the eIF4E kinase MNK1 to the eIF4G scaffold. |
Phospho-proteomics, site-directed mutagenesis of eIF4G1, phorbol ester activation of PKCα, co-immunoprecipitation |
Molecular and cellular biology |
Medium |
21576361
|
| 2011 |
MNK1 forms a complex with hnRNP A1 in vivo. Pharmacological inhibition of MNK1 decreases hnRNP A1 phosphorylation in young and senescent fibroblasts and blocks cytoplasmic accumulation of hnRNP A1 in senescent cells. MNK1 expression and phospho-MNK1 levels are elevated in senescent cells. |
Co-immunoprecipitation, pharmacological MNK1 inhibition (CGP57380), immunofluorescence, subcellular fractionation |
Experimental cell research |
Medium |
22227431
|
| 2012 |
RSK phosphorylates MNK1, and this phosphorylation is required for MNK1 to mediate trastuzumab resistance in HER2+ breast cancer cells. MNK1 is transcriptionally regulated by YB-1 (confirmed by ChIP-PCR). MNK1 overexpression alone is sufficient to confer trastuzumab resistance in previously sensitive cells. |
ChIP-sequencing, ChIP-PCR, siRNA knockdown, overexpression, RSK inhibitor BI-D1870, kinase assay |
Oncogene |
Medium |
22249268
|
| 2012 |
MNK1 kinase activity is required for cytokinesis/abscission; inhibition of MNK1 (chemical inhibitor, kinase-dead expression, or RNAi) induces multinucleated cells due to cytokinesis failure. Active MNK1 localizes to centrosomes, spindle microtubules, and the midbody. MNK1 depletion impairs centriolin localization at the midbody and consequently mislocalizes endobrevin (a v-SNARE), preventing membrane vesicle accumulation at the midbody. |
RNAi knockdown with rescue, kinase-dead mutant expression, chemical inhibitor, live-cell time-lapse imaging, immunofluorescence localization |
Journal of cell science |
High |
22454512
|
| 2012 |
TCR engagement activates MNK1/2 in primary T cells in a Ras-ERK1/2-dependent manner, which is inhibited by diacylglycerol kinases α and ζ. Mnk1/2 double deficiency abolishes TCR-induced eIF4E Ser209 phosphorylation. Mnk1/2 deficiency causes decreased IL-17 and IFN-γ production by CD4 T cells after immunization, correlating with milder experimental autoimmune encephalomyelitis. |
Double KO mice, TCR stimulation, pharmacological pathway inhibitors, cytokine assays, EAE model |
Journal of immunology |
High |
23269249
|
| 2013 |
MKNK1 facilitates hepatitis C virus (HCV) cell entry downstream of EGFR and ERK signaling; chemical inhibition or siRNA knockdown of MKNK1 significantly impairs entry of HCV genotype 1a and HCV-pseudotyped lentiviral particles with minimal impact on RNA replication. |
siRNA knockdown, chemical inhibitor panel, HCV pseudoparticle entry assay, replicon replication assay |
Journal of virology |
Medium |
23365451
|
| 2013 |
MNK1 is activated downstream of TAK1-p38 MAPK in neutrophils (not MEK/ERK, JNK, PI3K, or PKC). MNK1 controls cytokine protein synthesis (but not mRNA levels) and mediates the antiapoptotic effect of LPS/TNF-α via Mcl-1 translation. MNK1 inhibition decreases phosphorylation of S6K, S6, and hyperphosphorylated 4E-BP1, and partially impairs late PI3K/Akt activation. |
Pharmacological inhibition of multiple kinases, MNK1 overexpression, cytokine protein vs. mRNA measurement, apoptosis assays, cap-binding assay |
Journal of leukocyte biology |
Medium |
23401599
|
| 2014 |
MNK1 is a direct transcriptional target of the pancreatic transcription factor PTF1 (confirmed by ChIP). MNK1 is the principal eIF4E kinase in pancreatic acinar cells and is required for the physiological secretory response; Mnk1-/- acinar cells show defective enzyme relocalisation, polarity defects, and impaired secretory response in vitro and in vivo. |
Chromatin immunoprecipitation (ChIP), Mnk1 KO mice, secretin-stimulated MRI, in vitro amylase secretion assay, trypsinogen activation assay |
Gut |
High |
25037190
|
| 2014 |
MNK1 pathway activity maintains protein synthesis in rapalog-treated gliomas; combined MNK1 knockdown and mTORC1 inhibition profoundly increases 4EBP1 binding to eIF4E, inhibits 4EBP1 phosphorylation at Ser65, reduces protein synthesis and proliferation, and reduces tumor growth in an orthotopic GBM mouse model. |
Cap analog (m7GTP) pulldown with quantitative mass spectrometry proteomics, MNK1 knockdown, pharmacological MNK/mTORC1 inhibition, orthotopic mouse model |
The Journal of clinical investigation |
High |
24401275
|
| 2015 |
BDNF-induced upregulation of protein synthesis in cortical neurons requires MEK/ERK signaling and downstream MNK1, which phosphorylates eIF4E. MNK1 mediates BDNF-induced release of CYFIP1 (a translational repressor) from eIF4E. A subset of proteins involved in neurotransmission and synaptic plasticity has synthesis upregulated by BDNF via MNK1, with significant overlap with FMRP-bound mRNAs. |
Pharmacological and genetic approaches (Mnk1 KO), BONCAT+SILAC proteomics, co-immunoprecipitation (CYFIP1-eIF4E), protein synthesis measurement |
The Journal of neuroscience |
High |
25609615
|
| 2016 |
MNK1-knockout mice are protected against high-fat diet-induced glucose intolerance and insulin resistance (but not obesity or adipose inflammation), demonstrating a distinct role for MNK1 in mediating HFD-induced insulin resistance. |
MNK1 and MNK2 single KO mouse models, high-fat diet feeding, glucose tolerance test, insulin sensitivity test, adipose tissue inflammation analysis |
Scientific reports |
Medium |
27087055
|
| 2016 |
Mnk1 deficiency aggravates cardiac remodeling; Mnk1-KO mice show exaggerated hypertrophy, fibrosis, and dysfunction with increased ERK1/2 activation and reduced Sprouty2 expression. Overexpression of Sprouty2 rescues the exaggerated hypertrophic response in Mnk1-knockdown cardiomyocytes and in Mnk1-KO mice, placing MNK1 in the Sprouty2/ERK1/2 feedback pathway. |
Mnk1-KO mice with transverse aortic constriction, siRNA knockdown in NRVMs, adenoviral overexpression, Sprouty2 genetic rescue |
Hypertension |
High |
27698061
|
| 2017 |
C-KIT stimulates MNK1/2, which phosphorylate eIF4E and render it oncogenic in acral/mucosal melanoma; MNK1/2 depletion inhibits cell migration and mRNA translation of SNAI1 and CCNE1, identifying these as translational targets that drive oncogenicity. |
MNK1/2 depletion (genetic), MNK inhibitor SEL201, polysome profiling (implied), cell migration and tumor formation assays |
The Journal of clinical investigation |
Medium |
29035277
|
| 2018 |
Crystal structure-guided design of eFT508 (compound 23) reveals stereoelectronic interactions unique to MNK kinases; the inhibitor targets the ATP-binding site of MNK1/2 with exquisite selectivity. Crystal structure of MNK1 with inhibitor was used to guide medicinal chemistry. |
X-ray crystallography (structure-based drug design), kinase selectivity profiling, in vivo antitumor assays |
Journal of medicinal chemistry |
Medium |
29526098
|
| 2019 |
MNK1 knockout in breast DCIS cells represses NODAL expression, inhibits DCIS-to-IDC conversion, and decreases metastasis; constitutively active MNK1 induces NODAL expression and promotes IDC. The MNK1/NODAL axis promotes cancer stem cell properties and invasion, identifying NODAL as a translational/transcriptional target downstream of MNK1. |
MNK1 KO and constitutively active MNK1 cell lines, orthotopic mammary injection, in vitro invasion and stem cell assays, MNK inhibitor SEL201 in vivo |
Cancer research |
High |
30659022
|
| 2023 |
Mnk1/2 double knockout impairs synaptic plasticity and memory in mice independently of phospho-eIF4E (Ser209 ablation does not affect these processes). Syngap1 (a synaptic RasGAP encoded by an autism gene) co-immunoprecipitates with MNK1 and shows reduced phosphorylation at S788 in Mnk double-KO mice. Syngap1 knockdown reverses memory deficits in Mnk-DKO mice; pharmacological MNK inhibition rescues autism-related phenotypes in Syngap1+/- mice. |
Genetic double KO (Mnk1/2), phospho-eIF4E knock-in, co-immunoprecipitation (Syngap1-MNK1), translational profiling, Syngap1 knockdown rescue, behavioral assays |
Brain |
High |
36315645
|
| 2021 |
FICD (FMS intracellular domain fragment generated by M-CSF receptor c-FMS proteolysis) forms a complex with DAP5; the FICD/DAP5 axis promotes osteoclast differentiation by activating MNK1/2 and EIF4E phosphorylation, enhancing NFATc1 protein expression. MNK1/2 pathway inhibition diminishes arthritic bone erosion. |
Co-immunoprecipitation (FICD-DAP5), myeloid-specific FICD transgenic mice, MNK1/2 pharmacological inhibition, inflammatory arthritis model, osteoclast differentiation assays |
Bone research |
Medium |
34671034
|
| 2024 |
Loss of MNK1 restricts tumor cell metabolic adaptation by reducing glycolysis and increasing dependence on oxidative phosphorylation. MNK1-null breast and pancreatic tumor cells show suppressed metastasis specifically to the liver (but not the lung), identifying metabolic reprogramming as a consequence of MNK1 loss. |
MNK1 KO cancer cell lines, multi-omics (transcriptomics, proteomics, metabolomics), glycolysis/OXPHOS assays, in vivo metastasis models (liver vs. lung) |
Science advances |
High |
39270021
|