{"gene":"RPS6KA4","run_date":"2026-06-10T07:46:27","timeline":{"discoveries":[{"year":1998,"finding":"RSK-B (RPS6KA4/MSK2) was identified as a novel CREB kinase activated downstream of p38αMAPK (dominant control) and more weakly by ERK1. It phosphorylates CREB and c-Fos peptides, drives CRE- and AP1-dependent reporter expression in intracellular assays, and localizes to the cell nucleus, co-translocating p38αMAPK.","method":"p38αMAPK-baited intracellular interaction screen, in vitro kinase assays, reporter gene assays, subcellular localization imaging","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — multiple orthogonal methods (interaction screen, in vitro kinase assay, reporter assays, localization) in a single focused study establishing biochemical mechanism","pmids":["9792677"],"is_preprint":false},{"year":2002,"finding":"MSK1 and MSK2 are required for stress-induced phosphorylation of transcription factors CREB and ATF1 in primary embryonic fibroblasts, and doubly required for mitogen-induced CREB/ATF1 phosphorylation (greatly reduced but not abolished). Loss of both MSK1 and MSK2 reduced c-fos and junB transcription by ~50% in response to stress stimuli.","method":"MSK1 and MSK2 single and double knockout mice; primary embryonic fibroblast assays; immunoblotting for phospho-CREB/ATF1; RT-PCR for immediate-early gene expression","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic knockouts with defined cellular phosphorylation phenotype, replicated across multiple stimuli and multiple genes","pmids":["11909979"],"is_preprint":false},{"year":2003,"finding":"MSK2 (together with MSK1) is a major kinase responsible for mitogen- and stress-induced phosphorylation of histone H3 and HMG-14 in fibroblasts. Mice lacking both MSK1 and MSK2 show severely reduced or abolished histone H3 and HMG-14 phosphorylation in response to mitogens or stress stimuli. Histone H3 acetylation was unimpaired in these cells, and immediate-early genes could still be induced (though at reduced efficiency), establishing that MSK-mediated H3 phosphorylation is not required for H3 acetylation.","method":"MSK1/MSK2 double knockout mice; primary fibroblast assays; immunoblotting and immunofluorescence for phospho-H3 and phospho-HMG-14; chromatin immunoprecipitation","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean double-knockout genetic model with specific phosphorylation readouts, replicated across multiple stimuli and substrates in a single rigorous study","pmids":["12773393"],"is_preprint":false},{"year":2006,"finding":"MSK1 and MSK2 are required for EGF-induced, but not TNF-induced, histone H3 Ser10 phosphorylation both globally and at specific promoters. MSK1/2 are also required for optimal EGF-induced c-fos transcription and control EGF-induced IκBα promoter H3-Ser10 phosphorylation, demonstrating pathway-specific mechanisms for H3-Ser10 phosphorylation.","method":"MSK1/MSK2 knockout cells; siRNA knockdown; chromatin immunoprecipitation; immunoblotting; promoter-specific H3-Ser10 phosphorylation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic knockout plus ChIP with pathway-specific stimuli, multiple orthogonal methods in one study","pmids":["16517600"],"is_preprint":false},{"year":2008,"finding":"MSK1 and MSK2, acting downstream of p38 and ERK1/2 MAPKs, are required to limit proinflammatory cytokine production in LPS-stimulated macrophages. They do so by inducing transcription of DUSP1 and IL-10; MSK-deficient macrophages show impaired CREB and ATF1 binding to DUSP1 and IL-10 promoters. MSK1/MSK2 double-deficient mice are hypersensitive to LPS-induced endotoxic shock.","method":"MSK1/MSK2 double knockout mice; primary macrophage assays; ELISA for cytokines; ChIP for phospho-CREB/ATF1 at promoters; in vivo endotoxin shock model","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean double-knockout genetic model with ChIP, in vitro and in vivo readouts, multiple orthogonal methods","pmids":["18690222"],"is_preprint":false},{"year":2009,"finding":"CK2 protein kinase physically interacts with MSK2 but not MSK1, and CK2 inhibition specifically impairs UV-induced MSK2 kinase activation. CK2 phosphorylates MSK2 at Ser324; the S324A mutation compromises MSK2 activity. MSK2 (but not MSK1) is the major kinase responsible for UV-induced phosphorylation of NF-κB p65 at Ser276, promoting NF-κB transcriptional activity.","method":"Co-immunoprecipitation; RNAi knockdown; site-directed mutagenesis (S324A); in vivo phosphorylation assays; NF-κB reporter assays; CK2 pharmacological inhibition","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — direct interaction (Co-IP), mutagenesis of phosphorylation site, RNAi rescue experiments, multiple orthogonal methods in one study","pmids":["19933278"],"is_preprint":false},{"year":2009,"finding":"MSK2 inhibits p53 transcriptional activity in the absence of stress independently of its kinase activity and independently of upstream MAPK signaling. MSK2 physically interacts with and inhibits the p53 coactivator p300, and associates with the Noxa promoter. Apoptotic stimuli promote MSK2 degradation, thereby relieving p53 inhibition and enabling p53-dependent Noxa transactivation and apoptosis.","method":"Co-immunoprecipitation (MSK2-p300 interaction); kinase-dead MSK2 mutant; ChIP at Noxa promoter; p53 target gene expression analysis; apoptotic stimulus-induced MSK2 degradation assays","journal":"Science signaling","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, mutagenesis of kinase activity, ChIP, multiple orthogonal methods establishing mechanism in one focused study","pmids":["19797274"],"is_preprint":false},{"year":2011,"finding":"MSK2 binds PKR and stimulates PKR phosphorylation in the context of HCV infection, whereas the closely related MSK1 and RSK2 have no such effect. MSK2 functions as an adaptor to mediate PKR activation, apparently independent of its own catalytic activity.","method":"Co-immunoprecipitation (MSK2-PKR binding); in vitro and in vivo PKR phosphorylation assays; catalytically inactive MSK2 mutant; comparison with MSK1 and RSK2","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP plus kinase-dead mutant, single lab, single paper","pmids":["21385567"],"is_preprint":false},{"year":2013,"finding":"MSK1 and MSK2 promote IL-10 production in LPS-stimulated macrophages, which in turn provides negative feedback on cox-2 mRNA stability via a p38/MK2/TTP mechanism. MSK1/2 knockout macrophages show increased cox-2 mRNA stability, elevated cox-2 protein, and elevated prostaglandin secretion, demonstrating a role for MSK1/2 in limiting prostaglandin production through an IL-10 feedback loop.","method":"MSK1/MSK2 knockout macrophages; IL-10 neutralization/restoration experiments; mRNA stability assays; ELISA for prostaglandins; in vivo LPS injection model","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic knockout with defined molecular feedback mechanism, multiple orthogonal methods, in vitro and in vivo validation","pmids":["23382072"],"is_preprint":false},{"year":2013,"finding":"NF-κB activates RPS6KA4 gene expression, and RPS6KA4 inhibits p53 function (promoting p53 degradation). α-Lipoic acid downregulates RPS6KA4 mRNA via inhibition of NF-κB nuclear translocation, and restoration of RPS6KA4 expression attenuates α-LA-induced apoptosis in a p53-dependent manner.","method":"Microarray; RT-PCR; dominant-negative NF-κB transfection; NF-κB inhibitor (BAY11-7082); RPS6KA4 rescue expression; p53 wild-type vs. deficient cell comparison; Western blot","journal":"Anti-cancer drugs","confidence":"Medium","confidence_rationale":"Tier 2-3 / Weak — genetic rescue and dominant-negative approaches, single lab, limited direct mechanistic validation of RPS6KA4-p53 interaction","pmids":["23599020"],"is_preprint":false},{"year":2014,"finding":"Both MSK1 and MSK2 mediate LPA-induced phosphorylation of CREB at Ser133 and secretion of IL-8 and MCP-1 in fibroblast-like synoviocytes, acting downstream of ERK1/2 and p38 MAPK cascades. Silencing of CREB1 reduced LPA-induced chemokine production, placing CREB downstream of MSKs in this pathway.","method":"siRNA knockdown of MSK1, MSK2, and CREB1; pharmacological inhibitor SB747651A; immunoblotting for phospho-CREB; ELISA for IL-8 and MCP-1","journal":"Biochemical pharmacology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Weak — siRNA knockdown with defined phosphorylation and secretion readouts, single lab, single paper","pmids":["24792438"],"is_preprint":false},{"year":2016,"finding":"Msk2 promotes H3S10 phosphorylation (chromatin remodeling) in podocytes under high-glucose conditions. miR-93 targets Msk2 mRNA to reduce Msk2 expression, thereby altering nucleosomal dynamics and chromatin reorganization in diabetic nephropathy.","method":"Inducible podocyte-specific miR-93 transgenic mice; Western blot for Msk2 and H3S10 phosphorylation; chromatin accessibility assays; diabetic nephropathy model","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — in vivo transgenic model with defined substrate (H3S10) readout, single lab, mechanistic link to miR-93 regulation inferred but direct kinase assay not described in abstract","pmids":["27350436"],"is_preprint":false},{"year":2019,"finding":"MSK2 knockdown inhibited phosphorylation of PAX8 and retinoblastoma protein (RB), suppressed expression of E2F1 and cyclin A2, and inhibited squamous cervical cancer cell proliferation and tumor formation, placing MSK2 upstream of the PAX8/RB-E2F1/cyclin A2 proliferation axis.","method":"MSK2 siRNA knockdown; Western blot for phospho-PAX8, phospho-RB, E2F1, cyclin A2; cell proliferation assays; in vivo tumor formation assays","journal":"Journal of cellular biochemistry","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single knockdown study without direct kinase assay or mutagenesis to confirm MSK2-PAX8 as direct phosphorylation event","pmids":["30756420"],"is_preprint":false}],"current_model":"RPS6KA4 (MSK2) is a nuclear serine/threonine kinase activated downstream of p38 and ERK1/2 MAPKs that phosphorylates histone H3 (Ser10, Ser28) and HMG-14 to remodel chromatin at immediate-early gene promoters, phosphorylates CREB (Ser133) and ATF1 to drive transcription of anti-inflammatory mediators (IL-10, DUSP1) as a negative feedback brake on TLR-driven inflammation, and also phosphorylates NF-κB p65 (Ser276) specifically in response to UV via a CK2-mediated activation of MSK2 at Ser324; in addition, MSK2 acts as a kinase-activity-independent inhibitor of p53 by binding and suppressing the coactivator p300, and functions as a non-catalytic adaptor to promote PKR activation during viral infection."},"narrative":{"mechanistic_narrative":"RPS6KA4 (MSK2) is a nuclear serine/threonine kinase that operates at the convergence of the p38 and ERK1/2 MAPK cascades to couple mitogenic and stress signaling to chromatin remodeling and immediate-early gene transcription [PMID:9792677, PMID:11909979]. It was identified as a CREB kinase activated predominantly downstream of p38α and more weakly by ERK1, phosphorylating CREB and c-Fos and driving CRE- and AP1-dependent transcription [PMID:9792677]. Genetic ablation of MSK1/MSK2 established that these kinases are the major effectors of stress- and mitogen-induced phosphorylation of CREB and ATF1 and of the chromatin substrates histone H3 (Ser10) and HMG-14, with consequent control of immediate-early genes such as c-fos and junB in a pathway- and stimulus-specific manner [PMID:11909979, PMID:12773393, PMID:16517600]. Through CREB/ATF1-driven induction of DUSP1 and IL-10, MSK2 acts as a negative feedback brake on TLR/LPS-driven inflammation — MSK-deficient macrophages overproduce proinflammatory mediators and the IL-10 loop additionally restrains cox-2 mRNA stability and prostaglandin output, while MSK-deficient mice are hypersensitive to endotoxic shock [PMID:18690222, PMID:23382072]. MSK2 is also distinguished from MSK1 by a CK2-dependent activation arm: CK2 binds MSK2 and phosphorylates it at Ser324 to enable UV-induced phosphorylation of NF-κB p65 at Ser276 [PMID:19933278]. Beyond its catalytic functions, MSK2 has kinase-independent activities, binding and suppressing the p53 coactivator p300 to restrain p53 transcription in unstressed cells [PMID:19797274].","teleology":[{"year":1998,"claim":"Established MSK2 as a MAPK-activated nuclear CREB kinase, defining its position as an effector linking p38/ERK signaling to transcription-factor phosphorylation.","evidence":"p38αMAPK-baited interaction screen, in vitro kinase assays, reporter assays, and localization imaging","pmids":["9792677"],"confidence":"High","gaps":["Endogenous substrate repertoire not defined","Relative contribution of p38 vs ERK in vivo not resolved"]},{"year":2002,"claim":"Genetic knockouts demonstrated MSK1/MSK2 are the principal kinases for stress-induced CREB/ATF1 phosphorylation and contribute substantially to immediate-early gene induction, moving the model from biochemistry to physiology.","evidence":"MSK1/MSK2 single and double knockout mice, primary fibroblast phospho-immunoblotting, RT-PCR","pmids":["11909979"],"confidence":"High","gaps":["Residual mitogen-induced phosphorylation indicates other kinases contribute","Direct vs indirect contribution to gene induction not separated"]},{"year":2003,"claim":"Identified histone H3 and HMG-14 as chromatin substrates of MSK1/MSK2, establishing the kinases as a route by which signaling remodels chromatin at induced loci independently of H3 acetylation.","evidence":"MSK1/MSK2 double knockout fibroblasts, phospho-H3/HMG-14 immunoblotting and immunofluorescence, ChIP","pmids":["12773393"],"confidence":"High","gaps":["Functional consequence of H3 phosphorylation for transcription only partially defined","Genome-wide target loci not mapped"]},{"year":2006,"claim":"Showed that MSK-dependent H3-Ser10 phosphorylation is stimulus- and promoter-specific (EGF but not TNF), refining the model from a global to a pathway-selective chromatin mark.","evidence":"Knockout cells, siRNA, ChIP at specific promoters, promoter-specific H3-Ser10 assays","pmids":["16517600"],"confidence":"High","gaps":["Mechanism of pathway selectivity not defined","Promoter recruitment determinants unknown"]},{"year":2008,"claim":"Defined MSK1/MSK2 as an anti-inflammatory feedback module that induces DUSP1 and IL-10 to limit cytokine output, explaining the in vivo endotoxin hypersensitivity of MSK-deficient mice.","evidence":"MSK1/MSK2 double knockout macrophages, cytokine ELISA, ChIP for phospho-CREB/ATF1 at promoters, in vivo endotoxin shock model","pmids":["18690222"],"confidence":"High","gaps":["Relative roles of MSK1 vs MSK2 not dissected","Other anti-inflammatory targets beyond DUSP1/IL-10 not enumerated"]},{"year":2009,"claim":"Distinguished MSK2 from MSK1 by a CK2-Ser324 activation mechanism that drives UV-induced NF-κB p65 Ser276 phosphorylation, identifying a stimulus-specific signaling input unique to MSK2.","evidence":"Co-IP, RNAi, S324A mutagenesis, in vivo phosphorylation and NF-κB reporter assays, CK2 inhibition","pmids":["19933278"],"confidence":"High","gaps":["Structural basis of CK2-MSK2 selectivity unknown","Generality beyond UV stimulus not tested"]},{"year":2009,"claim":"Revealed a kinase-independent function in which MSK2 binds and suppresses p300 to restrain p53 transcription, with apoptotic MSK2 degradation relieving this brake.","evidence":"Reciprocal Co-IP, kinase-dead mutant, ChIP at Noxa promoter, p53 target expression, degradation assays","pmids":["19797274"],"confidence":"High","gaps":["Structural basis of MSK2-p300 interaction unknown","Degradation pathway/E3 ligase not identified"]},{"year":2011,"claim":"Proposed a second non-catalytic adaptor role in which MSK2 binds PKR to promote its activation during HCV infection, distinct from related kinases.","evidence":"Co-IP, in vitro/in vivo PKR phosphorylation assays, catalytically inactive mutant, comparison with MSK1/RSK2","pmids":["21385567"],"confidence":"Medium","gaps":["Single lab/single paper","Direct vs scaffold-mediated PKR activation not resolved"]},{"year":2013,"claim":"Extended the anti-inflammatory feedback model by linking MSK-driven IL-10 to suppression of cox-2 mRNA stability and prostaglandin production via p38/MK2/TTP.","evidence":"MSK1/MSK2 knockout macrophages, IL-10 neutralization/restoration, mRNA stability assays, prostaglandin ELISA, in vivo LPS model","pmids":["23382072"],"confidence":"High","gaps":["Quantitative contribution of this loop to overall inflammation resolution unclear"]},{"year":2013,"claim":"Placed RPS6KA4 in an NF-κB-driven transcriptional feedback that suppresses p53, with α-lipoic acid acting through NF-κB to downregulate RPS6KA4 and license apoptosis.","evidence":"Microarray, RT-PCR, dominant-negative NF-κB, NF-κB inhibitor, RPS6KA4 rescue, p53-WT vs -deficient comparison","pmids":["23599020"],"confidence":"Medium","gaps":["Direct MSK2-p53 mechanism not validated here","Single lab"]},{"year":2014,"claim":"Showed MSK1/MSK2 mediate LPA-induced CREB Ser133 phosphorylation and chemokine secretion in synoviocytes, extending the MAPK-MSK-CREB axis to a chemokine output.","evidence":"siRNA of MSK1/MSK2/CREB1, inhibitor SB747651A, phospho-CREB immunoblotting, IL-8/MCP-1 ELISA","pmids":["24792438"],"confidence":"Medium","gaps":["Direct kinase-substrate validation absent","MSK1 vs MSK2 contributions not separated"]},{"year":2016,"claim":"Linked Msk2-dependent H3S10 phosphorylation to chromatin reorganization in podocytes and identified miR-93 as an upstream regulator in diabetic nephropathy.","evidence":"Podocyte-specific miR-93 transgenic mice, Western blot for Msk2/H3S10, chromatin accessibility assays","pmids":["27350436"],"confidence":"Medium","gaps":["Direct kinase assay not described","miR-93-Msk2 targeting inferred"]},{"year":2019,"claim":"Associated MSK2 with a PAX8/RB-E2F1/cyclin A2 proliferation axis in cervical cancer cells.","evidence":"MSK2 siRNA knockdown, phospho-PAX8/RB and E2F1/cyclin A2 immunoblotting, proliferation and tumor formation assays","pmids":["30756420"],"confidence":"Low","gaps":["No direct kinase assay or mutagenesis confirming MSK2-PAX8 as a direct phosphorylation event","Single knockdown study"]},{"year":null,"claim":"How MSK2's catalytic and non-catalytic (p300-suppressing, PKR-adaptor) functions are coordinated, and what determines stimulus- and promoter-specific substrate selection, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model integrating kinase and scaffold roles","Determinants of promoter targeting unknown","MSK1 vs MSK2 functional divergence incompletely mapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,2,3,5]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0,2,5]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,6]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]},{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[2,3]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[4,8]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[2,3,11]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,1,4]}],"complexes":[],"partners":["MAPK14","CSNK2A1","EP300","EIF2AK2","CREB1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O75676","full_name":"Ribosomal protein S6 kinase alpha-4","aliases":["90 kDa ribosomal protein S6 kinase 4","Nuclear mitogen- and stress-activated protein kinase 2","Ribosomal protein kinase B","RSKB"],"length_aa":772,"mass_kda":85.6,"function":"Serine/threonine-protein kinase that is required for the mitogen or stress-induced phosphorylation of the transcription factors CREB1 and ATF1 and for the regulation of the transcription factor RELA, and that contributes to gene activation by histone phosphorylation and functions in the regulation of inflammatory genes. Phosphorylates CREB1 and ATF1 in response to mitogenic or stress stimuli such as UV-C irradiation, epidermal growth factor (EGF) and anisomycin. Plays an essential role in the control of RELA transcriptional activity in response to TNF. Phosphorylates 'Ser-10' of histone H3 in response to mitogenics, stress stimuli and EGF, which results in the transcriptional activation of several immediate early genes, including proto-oncogenes c-fos/FOS and c-jun/JUN. May also phosphorylate 'Ser-28' of histone H3. Mediates the mitogen- and stress-induced phosphorylation of high mobility group protein 1 (HMGN1/HMG14). In lipopolysaccharide-stimulated primary macrophages, acts downstream of the Toll-like receptor TLR4 to limit the production of pro-inflammatory cytokines. Functions probably by inducing transcription of the MAP kinase phosphatase DUSP1 and the anti-inflammatory cytokine interleukin 10 (IL10), via CREB1 and ATF1 transcription factors","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/O75676/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RPS6KA4","classification":"Not Classified","n_dependent_lines":13,"n_total_lines":1208,"dependency_fraction":0.01076158940397351},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000162302","cell_line_id":"CID001264","localizations":[{"compartment":"nucleoplasm","grade":3}],"interactors":[{"gene":"HIST2H2AA3;HIST2H2AC;H2AFJ","stoichiometry":0.2},{"gene":"RPS6KA1","stoichiometry":0.2},{"gene":"NCAPH","stoichiometry":0.2},{"gene":"SCOC","stoichiometry":0.2},{"gene":"BRCA1","stoichiometry":0.2},{"gene":"H1F0","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001264","total_profiled":1310},"omim":[{"mim_id":"603606","title":"RIBOSOMAL PROTEIN S6 KINASE A4; RPS6KA4","url":"https://www.omim.org/entry/603606"},{"mim_id":"602810","title":"HISTONE GENE CLUSTER 1, H3 HISTONE FAMILY, MEMBER A; HIST1H3A","url":"https://www.omim.org/entry/602810"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":54.3}],"url":"https://www.proteinatlas.org/search/RPS6KA4"},"hgnc":{"alias_symbol":["RSK-B","MSK2"],"prev_symbol":[]},"alphafold":{"accession":"O75676","domains":[{"cath_id":"3.30.200.20","chopping":"20-75_82-117","consensus_level":"high","plddt":74.125,"start":20,"end":117},{"cath_id":"1.10.510.10","chopping":"122-323","consensus_level":"high","plddt":82.3198,"start":122,"end":323},{"cath_id":"3.30.200.20","chopping":"391-485","consensus_level":"high","plddt":81.9032,"start":391,"end":485},{"cath_id":"1.10.510.10","chopping":"490-715","consensus_level":"high","plddt":73.9993,"start":490,"end":715}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O75676","model_url":"https://alphafold.ebi.ac.uk/files/AF-O75676-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O75676-F1-predicted_aligned_error_v6.png","plddt_mean":71.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RPS6KA4","jax_strain_url":"https://www.jax.org/strain/search?query=RPS6KA4"},"sequence":{"accession":"O75676","fasta_url":"https://rest.uniprot.org/uniprotkb/O75676.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O75676/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O75676"}},"corpus_meta":[{"pmid":"12773393","id":"PMC_12773393","title":"MSK2 and MSK1 mediate the mitogen- and stress-induced phosphorylation of histone H3 and HMG-14.","date":"2003","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/12773393","citation_count":411,"is_preprint":false},{"pmid":"11909979","id":"PMC_11909979","title":"MSK1 and MSK2 are required for the mitogen- and stress-induced phosphorylation of CREB and ATF1 in fibroblasts.","date":"2002","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/11909979","citation_count":375,"is_preprint":false},{"pmid":"18690222","id":"PMC_18690222","title":"The kinases MSK1 and MSK2 act as negative regulators of Toll-like receptor signaling.","date":"2008","source":"Nature immunology","url":"https://pubmed.ncbi.nlm.nih.gov/18690222","citation_count":271,"is_preprint":false},{"pmid":"9792677","id":"PMC_9792677","title":"RSK-B, a novel ribosomal S6 kinase family member, is a CREB kinase under dominant control of p38alpha mitogen-activated protein kinase (p38alphaMAPK).","date":"1998","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9792677","citation_count":141,"is_preprint":false},{"pmid":"27350436","id":"PMC_27350436","title":"miR-93 regulates Msk2-mediated chromatin remodelling in diabetic nephropathy.","date":"2016","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/27350436","citation_count":56,"is_preprint":false},{"pmid":"12915720","id":"PMC_12915720","title":"MSK1 and MSK2 mediate mitogen- and stress-induced phosphorylation of histone H3: a controversy resolved.","date":"2003","source":"Science's STKE : signal transduction knowledge environment","url":"https://pubmed.ncbi.nlm.nih.gov/12915720","citation_count":54,"is_preprint":false},{"pmid":"23382072","id":"PMC_23382072","title":"MSK1 and MSK2 inhibit lipopolysaccharide-induced prostaglandin production via an interleukin-10 feedback loop.","date":"2013","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/23382072","citation_count":35,"is_preprint":false},{"pmid":"16517600","id":"PMC_16517600","title":"The kinases MSK1 and MSK2 are required for epidermal growth factor-induced, but not tumor necrosis factor-induced, histone H3 Ser10 phosphorylation.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16517600","citation_count":35,"is_preprint":false},{"pmid":"21314333","id":"PMC_21314333","title":"Mice lacking MSK1 and MSK2 show reduced skin tumor development in a two-stage chemical carcinogenesis model.","date":"2011","source":"Cancer investigation","url":"https://pubmed.ncbi.nlm.nih.gov/21314333","citation_count":33,"is_preprint":false},{"pmid":"31889894","id":"PMC_31889894","title":"Sulforaphene induces apoptosis and inhibits the invasion of esophageal cancer cells through MSK2/CREB/Bcl-2 and cadherin pathway in vivo and in vitro.","date":"2019","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/31889894","citation_count":23,"is_preprint":false},{"pmid":"19933278","id":"PMC_19933278","title":"Differential regulation of mitogen- and stress-activated protein kinase-1 and -2 (MSK1 and MSK2) by CK2 following UV radiation.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19933278","citation_count":19,"is_preprint":false},{"pmid":"23599020","id":"PMC_23599020","title":"α-Lipoic acid prevents p53 degradation in colon cancer cells by blocking NF-κB induction of RPS6KA4.","date":"2013","source":"Anti-cancer drugs","url":"https://pubmed.ncbi.nlm.nih.gov/23599020","citation_count":18,"is_preprint":false},{"pmid":"32963350","id":"PMC_32963350","title":"Discovery of a novel dual-target inhibitor against RSK1 and MSK2 to suppress growth of human colon cancer.","date":"2020","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/32963350","citation_count":17,"is_preprint":false},{"pmid":"19797274","id":"PMC_19797274","title":"MSK2 inhibits p53 activity in the absence of stress.","date":"2009","source":"Science signaling","url":"https://pubmed.ncbi.nlm.nih.gov/19797274","citation_count":16,"is_preprint":false},{"pmid":"30756420","id":"PMC_30756420","title":"MSK2 promotes proliferation and tumor formation in squamous cervical cancer via PAX8/RB-E2F1/cyclin A2 axis.","date":"2019","source":"Journal of cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/30756420","citation_count":16,"is_preprint":false},{"pmid":"24792438","id":"PMC_24792438","title":"Lysophosphatidic acid-induced IL-8 secretion involves MSK1 and MSK2 mediated activation of CREB1 in human fibroblast-like synoviocytes.","date":"2014","source":"Biochemical pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/24792438","citation_count":12,"is_preprint":false},{"pmid":"28930610","id":"PMC_28930610","title":"RPS6KA4/MIR1237 and AURKC promoter regions are differentially methylated in Wilms' tumor.","date":"2018","source":"Frontiers in bioscience (Elite edition)","url":"https://pubmed.ncbi.nlm.nih.gov/28930610","citation_count":7,"is_preprint":false},{"pmid":"37278562","id":"PMC_37278562","title":"Potentially functional genetic variants in RPS6KA4 and MAP2K5 in the MAPK signaling pathway predict HBV-related hepatocellular carcinoma survival.","date":"2023","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/37278562","citation_count":4,"is_preprint":false},{"pmid":"21385567","id":"PMC_21385567","title":"HCV-induced PKR activation is stimulated by the mitogen- and stress-activated protein kinase MSK2.","date":"2011","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/21385567","citation_count":4,"is_preprint":false},{"pmid":"39467851","id":"PMC_39467851","title":"Prim-O-glucosylcimifugin alleviates influenza virus-induced pneumonia in mice by inhibiting the TGF-β1/PI3KCD/MSK2/RELA signalling pathway.","date":"2024","source":"Archives of virology","url":"https://pubmed.ncbi.nlm.nih.gov/39467851","citation_count":3,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11088,"output_tokens":3786,"usd":0.045027,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11456,"output_tokens":4262,"usd":0.081915,"stage2_stop_reason":"end_turn"},"total_usd":0.126942,"stage1_batch_id":"msgbatch_013LWZZT6MWaqB9qyTSeQBmU","stage2_batch_id":"msgbatch_0194ZzQaTGNpruoNJBbEMbt3","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"RSK-B (RPS6KA4/MSK2) was identified as a novel CREB kinase activated downstream of p38αMAPK (dominant control) and more weakly by ERK1. It phosphorylates CREB and c-Fos peptides, drives CRE- and AP1-dependent reporter expression in intracellular assays, and localizes to the cell nucleus, co-translocating p38αMAPK.\",\n      \"method\": \"p38αMAPK-baited intracellular interaction screen, in vitro kinase assays, reporter gene assays, subcellular localization imaging\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — multiple orthogonal methods (interaction screen, in vitro kinase assay, reporter assays, localization) in a single focused study establishing biochemical mechanism\",\n      \"pmids\": [\"9792677\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"MSK1 and MSK2 are required for stress-induced phosphorylation of transcription factors CREB and ATF1 in primary embryonic fibroblasts, and doubly required for mitogen-induced CREB/ATF1 phosphorylation (greatly reduced but not abolished). Loss of both MSK1 and MSK2 reduced c-fos and junB transcription by ~50% in response to stress stimuli.\",\n      \"method\": \"MSK1 and MSK2 single and double knockout mice; primary embryonic fibroblast assays; immunoblotting for phospho-CREB/ATF1; RT-PCR for immediate-early gene expression\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic knockouts with defined cellular phosphorylation phenotype, replicated across multiple stimuli and multiple genes\",\n      \"pmids\": [\"11909979\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"MSK2 (together with MSK1) is a major kinase responsible for mitogen- and stress-induced phosphorylation of histone H3 and HMG-14 in fibroblasts. Mice lacking both MSK1 and MSK2 show severely reduced or abolished histone H3 and HMG-14 phosphorylation in response to mitogens or stress stimuli. Histone H3 acetylation was unimpaired in these cells, and immediate-early genes could still be induced (though at reduced efficiency), establishing that MSK-mediated H3 phosphorylation is not required for H3 acetylation.\",\n      \"method\": \"MSK1/MSK2 double knockout mice; primary fibroblast assays; immunoblotting and immunofluorescence for phospho-H3 and phospho-HMG-14; chromatin immunoprecipitation\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean double-knockout genetic model with specific phosphorylation readouts, replicated across multiple stimuli and substrates in a single rigorous study\",\n      \"pmids\": [\"12773393\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"MSK1 and MSK2 are required for EGF-induced, but not TNF-induced, histone H3 Ser10 phosphorylation both globally and at specific promoters. MSK1/2 are also required for optimal EGF-induced c-fos transcription and control EGF-induced IκBα promoter H3-Ser10 phosphorylation, demonstrating pathway-specific mechanisms for H3-Ser10 phosphorylation.\",\n      \"method\": \"MSK1/MSK2 knockout cells; siRNA knockdown; chromatin immunoprecipitation; immunoblotting; promoter-specific H3-Ser10 phosphorylation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout plus ChIP with pathway-specific stimuli, multiple orthogonal methods in one study\",\n      \"pmids\": [\"16517600\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"MSK1 and MSK2, acting downstream of p38 and ERK1/2 MAPKs, are required to limit proinflammatory cytokine production in LPS-stimulated macrophages. They do so by inducing transcription of DUSP1 and IL-10; MSK-deficient macrophages show impaired CREB and ATF1 binding to DUSP1 and IL-10 promoters. MSK1/MSK2 double-deficient mice are hypersensitive to LPS-induced endotoxic shock.\",\n      \"method\": \"MSK1/MSK2 double knockout mice; primary macrophage assays; ELISA for cytokines; ChIP for phospho-CREB/ATF1 at promoters; in vivo endotoxin shock model\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean double-knockout genetic model with ChIP, in vitro and in vivo readouts, multiple orthogonal methods\",\n      \"pmids\": [\"18690222\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"CK2 protein kinase physically interacts with MSK2 but not MSK1, and CK2 inhibition specifically impairs UV-induced MSK2 kinase activation. CK2 phosphorylates MSK2 at Ser324; the S324A mutation compromises MSK2 activity. MSK2 (but not MSK1) is the major kinase responsible for UV-induced phosphorylation of NF-κB p65 at Ser276, promoting NF-κB transcriptional activity.\",\n      \"method\": \"Co-immunoprecipitation; RNAi knockdown; site-directed mutagenesis (S324A); in vivo phosphorylation assays; NF-κB reporter assays; CK2 pharmacological inhibition\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — direct interaction (Co-IP), mutagenesis of phosphorylation site, RNAi rescue experiments, multiple orthogonal methods in one study\",\n      \"pmids\": [\"19933278\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"MSK2 inhibits p53 transcriptional activity in the absence of stress independently of its kinase activity and independently of upstream MAPK signaling. MSK2 physically interacts with and inhibits the p53 coactivator p300, and associates with the Noxa promoter. Apoptotic stimuli promote MSK2 degradation, thereby relieving p53 inhibition and enabling p53-dependent Noxa transactivation and apoptosis.\",\n      \"method\": \"Co-immunoprecipitation (MSK2-p300 interaction); kinase-dead MSK2 mutant; ChIP at Noxa promoter; p53 target gene expression analysis; apoptotic stimulus-induced MSK2 degradation assays\",\n      \"journal\": \"Science signaling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, mutagenesis of kinase activity, ChIP, multiple orthogonal methods establishing mechanism in one focused study\",\n      \"pmids\": [\"19797274\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"MSK2 binds PKR and stimulates PKR phosphorylation in the context of HCV infection, whereas the closely related MSK1 and RSK2 have no such effect. MSK2 functions as an adaptor to mediate PKR activation, apparently independent of its own catalytic activity.\",\n      \"method\": \"Co-immunoprecipitation (MSK2-PKR binding); in vitro and in vivo PKR phosphorylation assays; catalytically inactive MSK2 mutant; comparison with MSK1 and RSK2\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP plus kinase-dead mutant, single lab, single paper\",\n      \"pmids\": [\"21385567\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"MSK1 and MSK2 promote IL-10 production in LPS-stimulated macrophages, which in turn provides negative feedback on cox-2 mRNA stability via a p38/MK2/TTP mechanism. MSK1/2 knockout macrophages show increased cox-2 mRNA stability, elevated cox-2 protein, and elevated prostaglandin secretion, demonstrating a role for MSK1/2 in limiting prostaglandin production through an IL-10 feedback loop.\",\n      \"method\": \"MSK1/MSK2 knockout macrophages; IL-10 neutralization/restoration experiments; mRNA stability assays; ELISA for prostaglandins; in vivo LPS injection model\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic knockout with defined molecular feedback mechanism, multiple orthogonal methods, in vitro and in vivo validation\",\n      \"pmids\": [\"23382072\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"NF-κB activates RPS6KA4 gene expression, and RPS6KA4 inhibits p53 function (promoting p53 degradation). α-Lipoic acid downregulates RPS6KA4 mRNA via inhibition of NF-κB nuclear translocation, and restoration of RPS6KA4 expression attenuates α-LA-induced apoptosis in a p53-dependent manner.\",\n      \"method\": \"Microarray; RT-PCR; dominant-negative NF-κB transfection; NF-κB inhibitor (BAY11-7082); RPS6KA4 rescue expression; p53 wild-type vs. deficient cell comparison; Western blot\",\n      \"journal\": \"Anti-cancer drugs\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Weak — genetic rescue and dominant-negative approaches, single lab, limited direct mechanistic validation of RPS6KA4-p53 interaction\",\n      \"pmids\": [\"23599020\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Both MSK1 and MSK2 mediate LPA-induced phosphorylation of CREB at Ser133 and secretion of IL-8 and MCP-1 in fibroblast-like synoviocytes, acting downstream of ERK1/2 and p38 MAPK cascades. Silencing of CREB1 reduced LPA-induced chemokine production, placing CREB downstream of MSKs in this pathway.\",\n      \"method\": \"siRNA knockdown of MSK1, MSK2, and CREB1; pharmacological inhibitor SB747651A; immunoblotting for phospho-CREB; ELISA for IL-8 and MCP-1\",\n      \"journal\": \"Biochemical pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Weak — siRNA knockdown with defined phosphorylation and secretion readouts, single lab, single paper\",\n      \"pmids\": [\"24792438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Msk2 promotes H3S10 phosphorylation (chromatin remodeling) in podocytes under high-glucose conditions. miR-93 targets Msk2 mRNA to reduce Msk2 expression, thereby altering nucleosomal dynamics and chromatin reorganization in diabetic nephropathy.\",\n      \"method\": \"Inducible podocyte-specific miR-93 transgenic mice; Western blot for Msk2 and H3S10 phosphorylation; chromatin accessibility assays; diabetic nephropathy model\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — in vivo transgenic model with defined substrate (H3S10) readout, single lab, mechanistic link to miR-93 regulation inferred but direct kinase assay not described in abstract\",\n      \"pmids\": [\"27350436\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"MSK2 knockdown inhibited phosphorylation of PAX8 and retinoblastoma protein (RB), suppressed expression of E2F1 and cyclin A2, and inhibited squamous cervical cancer cell proliferation and tumor formation, placing MSK2 upstream of the PAX8/RB-E2F1/cyclin A2 proliferation axis.\",\n      \"method\": \"MSK2 siRNA knockdown; Western blot for phospho-PAX8, phospho-RB, E2F1, cyclin A2; cell proliferation assays; in vivo tumor formation assays\",\n      \"journal\": \"Journal of cellular biochemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single knockdown study without direct kinase assay or mutagenesis to confirm MSK2-PAX8 as direct phosphorylation event\",\n      \"pmids\": [\"30756420\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RPS6KA4 (MSK2) is a nuclear serine/threonine kinase activated downstream of p38 and ERK1/2 MAPKs that phosphorylates histone H3 (Ser10, Ser28) and HMG-14 to remodel chromatin at immediate-early gene promoters, phosphorylates CREB (Ser133) and ATF1 to drive transcription of anti-inflammatory mediators (IL-10, DUSP1) as a negative feedback brake on TLR-driven inflammation, and also phosphorylates NF-κB p65 (Ser276) specifically in response to UV via a CK2-mediated activation of MSK2 at Ser324; in addition, MSK2 acts as a kinase-activity-independent inhibitor of p53 by binding and suppressing the coactivator p300, and functions as a non-catalytic adaptor to promote PKR activation during viral infection.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"RPS6KA4 (MSK2) is a nuclear serine/threonine kinase that operates at the convergence of the p38 and ERK1/2 MAPK cascades to couple mitogenic and stress signaling to chromatin remodeling and immediate-early gene transcription [#0, #1]. It was identified as a CREB kinase activated predominantly downstream of p38\\u03b1 and more weakly by ERK1, phosphorylating CREB and c-Fos and driving CRE- and AP1-dependent transcription [#0]. Genetic ablation of MSK1/MSK2 established that these kinases are the major effectors of stress- and mitogen-induced phosphorylation of CREB and ATF1 and of the chromatin substrates histone H3 (Ser10) and HMG-14, with consequent control of immediate-early genes such as c-fos and junB in a pathway- and stimulus-specific manner [#1, #2, #3]. Through CREB/ATF1-driven induction of DUSP1 and IL-10, MSK2 acts as a negative feedback brake on TLR/LPS-driven inflammation \\u2014 MSK-deficient macrophages overproduce proinflammatory mediators and the IL-10 loop additionally restrains cox-2 mRNA stability and prostaglandin output, while MSK-deficient mice are hypersensitive to endotoxic shock [#4, #8]. MSK2 is also distinguished from MSK1 by a CK2-dependent activation arm: CK2 binds MSK2 and phosphorylates it at Ser324 to enable UV-induced phosphorylation of NF-\\u03baB p65 at Ser276 [#5]. Beyond its catalytic functions, MSK2 has kinase-independent activities, binding and suppressing the p53 coactivator p300 to restrain p53 transcription in unstressed cells [#6].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established MSK2 as a MAPK-activated nuclear CREB kinase, defining its position as an effector linking p38/ERK signaling to transcription-factor phosphorylation.\",\n      \"evidence\": \"p38\\u03b1MAPK-baited interaction screen, in vitro kinase assays, reporter assays, and localization imaging\",\n      \"pmids\": [\"9792677\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endogenous substrate repertoire not defined\", \"Relative contribution of p38 vs ERK in vivo not resolved\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Genetic knockouts demonstrated MSK1/MSK2 are the principal kinases for stress-induced CREB/ATF1 phosphorylation and contribute substantially to immediate-early gene induction, moving the model from biochemistry to physiology.\",\n      \"evidence\": \"MSK1/MSK2 single and double knockout mice, primary fibroblast phospho-immunoblotting, RT-PCR\",\n      \"pmids\": [\"11909979\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Residual mitogen-induced phosphorylation indicates other kinases contribute\", \"Direct vs indirect contribution to gene induction not separated\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identified histone H3 and HMG-14 as chromatin substrates of MSK1/MSK2, establishing the kinases as a route by which signaling remodels chromatin at induced loci independently of H3 acetylation.\",\n      \"evidence\": \"MSK1/MSK2 double knockout fibroblasts, phospho-H3/HMG-14 immunoblotting and immunofluorescence, ChIP\",\n      \"pmids\": [\"12773393\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of H3 phosphorylation for transcription only partially defined\", \"Genome-wide target loci not mapped\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Showed that MSK-dependent H3-Ser10 phosphorylation is stimulus- and promoter-specific (EGF but not TNF), refining the model from a global to a pathway-selective chromatin mark.\",\n      \"evidence\": \"Knockout cells, siRNA, ChIP at specific promoters, promoter-specific H3-Ser10 assays\",\n      \"pmids\": [\"16517600\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of pathway selectivity not defined\", \"Promoter recruitment determinants unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defined MSK1/MSK2 as an anti-inflammatory feedback module that induces DUSP1 and IL-10 to limit cytokine output, explaining the in vivo endotoxin hypersensitivity of MSK-deficient mice.\",\n      \"evidence\": \"MSK1/MSK2 double knockout macrophages, cytokine ELISA, ChIP for phospho-CREB/ATF1 at promoters, in vivo endotoxin shock model\",\n      \"pmids\": [\"18690222\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative roles of MSK1 vs MSK2 not dissected\", \"Other anti-inflammatory targets beyond DUSP1/IL-10 not enumerated\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Distinguished MSK2 from MSK1 by a CK2-Ser324 activation mechanism that drives UV-induced NF-\\u03baB p65 Ser276 phosphorylation, identifying a stimulus-specific signaling input unique to MSK2.\",\n      \"evidence\": \"Co-IP, RNAi, S324A mutagenesis, in vivo phosphorylation and NF-\\u03baB reporter assays, CK2 inhibition\",\n      \"pmids\": [\"19933278\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of CK2-MSK2 selectivity unknown\", \"Generality beyond UV stimulus not tested\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Revealed a kinase-independent function in which MSK2 binds and suppresses p300 to restrain p53 transcription, with apoptotic MSK2 degradation relieving this brake.\",\n      \"evidence\": \"Reciprocal Co-IP, kinase-dead mutant, ChIP at Noxa promoter, p53 target expression, degradation assays\",\n      \"pmids\": [\"19797274\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of MSK2-p300 interaction unknown\", \"Degradation pathway/E3 ligase not identified\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Proposed a second non-catalytic adaptor role in which MSK2 binds PKR to promote its activation during HCV infection, distinct from related kinases.\",\n      \"evidence\": \"Co-IP, in vitro/in vivo PKR phosphorylation assays, catalytically inactive mutant, comparison with MSK1/RSK2\",\n      \"pmids\": [\"21385567\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab/single paper\", \"Direct vs scaffold-mediated PKR activation not resolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Extended the anti-inflammatory feedback model by linking MSK-driven IL-10 to suppression of cox-2 mRNA stability and prostaglandin production via p38/MK2/TTP.\",\n      \"evidence\": \"MSK1/MSK2 knockout macrophages, IL-10 neutralization/restoration, mRNA stability assays, prostaglandin ELISA, in vivo LPS model\",\n      \"pmids\": [\"23382072\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative contribution of this loop to overall inflammation resolution unclear\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Placed RPS6KA4 in an NF-\\u03baB-driven transcriptional feedback that suppresses p53, with \\u03b1-lipoic acid acting through NF-\\u03baB to downregulate RPS6KA4 and license apoptosis.\",\n      \"evidence\": \"Microarray, RT-PCR, dominant-negative NF-\\u03baB, NF-\\u03baB inhibitor, RPS6KA4 rescue, p53-WT vs -deficient comparison\",\n      \"pmids\": [\"23599020\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct MSK2-p53 mechanism not validated here\", \"Single lab\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Showed MSK1/MSK2 mediate LPA-induced CREB Ser133 phosphorylation and chemokine secretion in synoviocytes, extending the MAPK-MSK-CREB axis to a chemokine output.\",\n      \"evidence\": \"siRNA of MSK1/MSK2/CREB1, inhibitor SB747651A, phospho-CREB immunoblotting, IL-8/MCP-1 ELISA\",\n      \"pmids\": [\"24792438\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct kinase-substrate validation absent\", \"MSK1 vs MSK2 contributions not separated\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Linked Msk2-dependent H3S10 phosphorylation to chromatin reorganization in podocytes and identified miR-93 as an upstream regulator in diabetic nephropathy.\",\n      \"evidence\": \"Podocyte-specific miR-93 transgenic mice, Western blot for Msk2/H3S10, chromatin accessibility assays\",\n      \"pmids\": [\"27350436\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct kinase assay not described\", \"miR-93-Msk2 targeting inferred\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Associated MSK2 with a PAX8/RB-E2F1/cyclin A2 proliferation axis in cervical cancer cells.\",\n      \"evidence\": \"MSK2 siRNA knockdown, phospho-PAX8/RB and E2F1/cyclin A2 immunoblotting, proliferation and tumor formation assays\",\n      \"pmids\": [\"30756420\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct kinase assay or mutagenesis confirming MSK2-PAX8 as a direct phosphorylation event\", \"Single knockdown study\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MSK2's catalytic and non-catalytic (p300-suppressing, PKR-adaptor) functions are coordinated, and what determines stimulus- and promoter-specific substrate selection, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model integrating kinase and scaffold roles\", \"Determinants of promoter targeting unknown\", \"MSK1 vs MSK2 functional divergence incompletely mapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 2, 3, 5]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0, 2, 5]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [4, 8]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [2, 3, 11]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 1, 4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"MAPK14\", \"CSNK2A1\", \"EP300\", \"EIF2AK2\", \"CREB1\"],\n    \"other_free_text\": []\n  }\n}\n```","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}