{"gene":"AKIRIN2","run_date":"2026-06-09T22:02:43","timeline":{"discoveries":[{"year":2021,"finding":"AKIRIN2 forms homodimers that directly bind to fully assembled 20S proteasomes and mediates their nuclear import in vertebrates. During mitosis, proteasomes are excluded from condensing chromatin and re-imported into newly formed daughter nuclei in an AKIRIN2-dependent process. Cells lacking AKIRIN2 become devoid of nuclear proteasomes, causing accumulation of MYC and other nuclear proteins.","method":"CRISPR screen, Co-IP, intracellular immunostaining, FACS, live cell imaging, biochemical fractionation","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct binding demonstrated biochemically, functional consequence of loss established by multiple orthogonal methods including CRISPR screen, Co-IP, and live imaging","pmids":["34711951"],"is_preprint":false},{"year":2024,"finding":"AKIRIN2 acts as a scaffold/adaptor protein that coordinates stepwise assembly of an importin cluster around the proteasome. A wing helix in a disordered region of AKIRIN2 stabilizes proteasome interactions. AKIRIN2 homodimers recruit importin IPO9, which facilitates binding of a second AKIRIN2 homodimer that recruits additional importins, creating a multivalent assembly that amplifies nuclear localization signals for efficient proteasome translocation. Inside the nucleus, RanGTP dissociates importins, and AKIRIN2 is degraded by the proteasome in a ubiquitin-independent manner.","method":"Protein-wide saturation mutagenesis screens (FACS- and microscopy-based), cryo-EM, biochemical reconstitution","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure combined with saturation mutagenesis and biochemical reconstitution; multiple orthogonal methods in a single rigorous study","pmids":["bio_10.1101_2024.11.08.622636"],"is_preprint":true},{"year":2014,"finding":"Akirin2 bridges the NF-κB pathway and the SWI/SNF chromatin remodeling complex by interacting with BAF60 proteins and IκB-ζ (which forms a complex with NF-κB p50). This IκB-ζ–Akirin2–BAF60 complex is essential for TLR-, RIG-I-, and Listeria-mediated induction of proinflammatory genes (Il6, Il12b) in macrophages. Akirin2 and IκB-ζ mutually depend on each other for recruitment to the Il6 promoter.","method":"Co-immunoprecipitation, chromatin immunoprecipitation, macrophage-specific knockout, reporter assays, infection models","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, ChIP, genetic KO with specific phenotypic readouts, multiple stimuli tested, independently replicated across related studies","pmids":["25107474"],"is_preprint":false},{"year":2015,"finding":"Akirin2 is required for B cell cycle progression and humoral immune responses by controlling the SWI/SNF complex. Akirin2-deficient B cells show defective expression of cyclin D and c-Myc, and impaired Brg1 recruitment to Myc and Ccnd2 promoters. B cell-specific knockout leads to decreased follicular and peritoneal B-1 cell numbers, defective proliferation, and apoptosis in response to TLR ligands, CD40, and BCR stimulation.","method":"B cell-specific conditional knockout (Cd19-Cre), chromatin immunoprecipitation, flow cytometry, in vivo immunization","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional KO with specific promoter-level ChIP evidence and multiple orthogonal readouts in vivo and in vitro","pmids":["26041538"],"is_preprint":false},{"year":2013,"finding":"FBI1/Akirin2 forms a complex with 14-3-3β that acts as a transcriptional repressor binding to the BCAM promoter, suppressing BCAM expression and thereby promoting tumorigenicity and metastasis.","method":"Luciferase reporter assay, chromatin immunoprecipitation, antisense knockdown, in vivo tumor assay","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and reporter assays confirm promoter binding, functional KD validated in vivo, single lab","pmids":["24223164"],"is_preprint":false},{"year":2017,"finding":"Akirin2 regulates proliferation and differentiation of porcine skeletal muscle satellite cells through ERK1/2 and NFATc1 signaling pathways, as demonstrated by overexpression and siRNA knockdown experiments.","method":"Overexpression and siRNA knockdown, western blot, cell proliferation/differentiation assays","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — gain- and loss-of-function with pathway readouts, single lab, no direct binding or structural data","pmids":["28327665"],"is_preprint":false},{"year":2016,"finding":"Akirin2 is required for early cortical progenitor survival and proliferation during cerebral cortex formation. Loss of Akirin2 in cortical progenitors causes massive apoptosis starting at E10, failure of normal proliferation, and defective Wnt3a signaling/cortical hem formation.","method":"Cortex-restricted conditional knockout (Emx1-Cre), EdU labeling, in situ hybridization, immunohistochemistry","journal":"Neural development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with specific cellular and molecular phenotypes, EdU and ISH, single lab","pmids":["27871306"],"is_preprint":false},{"year":2017,"finding":"Akirin2 in Xenopus neural development acts upstream of BAF53a-containing BAF complex to maintain neural progenitor state (regulating Sox2 expression antagonistically to Geminin), and also acts upstream of NeuroD and in parallel with Ngnr1 for terminal neuronal differentiation (regulating N-tubulin expression).","method":"Xenopus knockdown, epistasis analysis, rescue experiments, in situ hybridization","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis established by double-knockdown rescue in Xenopus, single lab","pmids":["28193841"],"is_preprint":false},{"year":2022,"finding":"Akirin2 loss in mature cortical neurons causes progressive neurodegeneration via necroptosis, associated with upregulation of p53 (Trp53) target genes. Genetic reduction of Trp53 rescued neurodegeneration in Akirin2-null neurons, placing Akirin2 upstream of p53-mediated cell death pathways.","method":"Neuron-specific conditional knockout, transcriptomics, genetic epistasis (Trp53 reduction rescue), histology","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with transcriptomic analysis and genetic rescue establishing pathway placement, single lab","pmids":["35198879"],"is_preprint":false},{"year":2019,"finding":"Akirin2 is required for mammalian myogenesis in vivo; loss in somitic muscle precursors via Sim1-Cre leads to neonatal lethality, absence of forelimb/intercostal/diaphragm muscles due to apoptosis of Pax3-positive myoblasts, and impaired expression of myogenin and myosin heavy chain during muscle cell differentiation in vitro.","method":"Conditional knockout (Sim1-Cre), immunohistochemistry, in vitro differentiation assays, western blot","journal":"Genesis","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with molecular marker analysis in vivo and in vitro, single lab","pmids":["30801883"],"is_preprint":false},{"year":2018,"finding":"Akirin2 is required for interdigital tissue regression in the mouse limb; knockout in limb epithelium leads to loss of interdigital cell death, increased cell proliferation, and soft-tissue syndactyly. This is associated with perdurance of Fgf8 expression, implicating Akirin2 in downregulation of Fgf8 from the apical ectodermal ridge.","method":"Conditional knockout in limb epithelium, immunohistochemistry, in situ hybridization","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with molecular marker evidence, pathway placement via Fgf8 expression analysis, single lab","pmids":["30116001"],"is_preprint":false},{"year":2017,"finding":"Akirin2 promotes slow MyHC I expression via calcineurin (CaN)/NFATc1 signaling pathway in porcine skeletal muscle satellite cells; knockdown of Akirin2 decreases CaN activity and NFATc1 expression, while overexpression has the opposite effect, and inhibition of CaN or NFATc1 knockdown blocks Akirin2 overexpression-induced upregulation of MyHC I.","method":"siRNA knockdown, overexpression, pharmacological inhibition, western blot, qPCR","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — pathway placement by genetic epistasis (inhibitor/siRNA rescue), single lab, no direct binding data","pmids":["28223540"],"is_preprint":false},{"year":2016,"finding":"Duck Akirin2 promotes myoblast proliferation (but not differentiation) via activation of the mTOR/p70S6K signaling pathway; rapamycin blocks Akirin2-induced increases in cell viability, mTOR and p70S6K mRNA, and phospho-mTOR/phospho-p70S6K protein levels.","method":"Overexpression, pharmacological inhibition (rapamycin), flow cytometry, western blot","journal":"The international journal of biochemistry & cell biology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, pharmacological inhibitor only, no direct binding or genetic epistasis","pmids":["27590857"],"is_preprint":false},{"year":2024,"finding":"AjAkirin2 (sea cucumber ortholog) directly interacts with Aj14-3-3ζ as demonstrated by GST-pulldown and co-IP assays. AjAkirin2 positively regulates Aj14-3-3ζ expression, and knockdown of either protein increases intracellular bacterial load and suppresses NF-κB signaling pathway genes and inflammatory cytokines.","method":"GST-pulldown, co-immunoprecipitation, RNAi knockdown, bacterial load assay, qPCR","journal":"Fish & shellfish immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding confirmed by two orthogonal pulldown methods, functional consequence of KD demonstrated, invertebrate ortholog","pmids":["38685443"],"is_preprint":false},{"year":2019,"finding":"Akirin2 induces angiogenesis in cholangiocarcinoma by increasing VEGFA expression through activation of the IL-6/STAT3 signaling pathway, and promotes EMT-associated migration and invasion. miR-490-3p negatively regulates Akirin2 expression at the post-transcriptional level via its 3'-UTR.","method":"Lentiviral knockdown/overexpression, luciferase reporter assay (3'-UTR), in vivo tumor model, western blot","journal":"Cell death & disease","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pathway placement by KD/OE without direct binding evidence, single lab, cancer cell line context","pmids":["30886152"],"is_preprint":false},{"year":2014,"finding":"FBI1/Akirin2 downregulation in Lewis lung carcinoma cells decreased anchorage-independent growth and reduced tumor growth and metastasis in vivo, indicating FBI1/Akirin2 overexpression is required for LLC1 tumor growth and metastasis.","method":"Antisense knockdown, in vitro anchorage-independent growth assay, in vivo nude mouse tumor assay","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — KD with phenotypic readout, no molecular mechanism established beyond the 14-3-3β complex described in companion paper, single lab","pmids":["24468084"],"is_preprint":false}],"current_model":"AKIRIN2 is a conserved nuclear scaffold protein with two key mechanistic roles: (1) it forms homodimers that directly bind fully assembled 20S proteasomes and recruit importins (including IPO9) via a multivalent adaptor mechanism to drive nuclear import of proteasomes in vertebrates, a process essential for nuclear protein homeostasis; and (2) it bridges NF-κB signaling (via IκB-ζ/p50) to the SWI/SNF chromatin remodeling complex (via BAF60 proteins) to enable transcriptional activation of proinflammatory genes, B cell cycle progression, and chromatin remodeling during development and immunity."},"narrative":{"mechanistic_narrative":"AKIRIN2 is a conserved nuclear protein that functions dually as an importin-coupled adaptor for proteasome nuclear import and as a transcriptional scaffold bridging signaling to chromatin remodeling [PMID:34711951, PMID:25107474]. As a homodimer, it binds directly to fully assembled 20S proteasomes and is required for their nuclear import; cells lacking AKIRIN2 lose nuclear proteasomes and accumulate nuclear substrates such as MYC, and during mitosis AKIRIN2 re-imports proteasomes into newly formed daughter nuclei [PMID:34711951]. Mechanistically, a wing helix within a disordered region stabilizes the proteasome interaction, and AKIRIN2 homodimers nucleate stepwise recruitment of importins (including IPO9) into a multivalent cluster that amplifies nuclear localization signals for efficient translocation, after which RanGTP releases the importins and AKIRIN2 is degraded by the proteasome in a ubiquitin-independent manner [PMID:bio_10.1101_2024.11.08.622636]. In its transcriptional role, AKIRIN2 links the NF-κB pathway to the SWI/SNF complex by interacting with BAF60 proteins and with IκB-ζ (in complex with NF-κB p50), an interaction required for induction of proinflammatory genes such as Il6 and Il12b in macrophages and for Brg1 recruitment to Myc and Ccnd2 promoters driving B cell proliferation [PMID:25107474, PMID:26041538]. Consistent with a chromatin-remodeling role acting upstream of progenitor maintenance and cell-survival programs, AKIRIN2 is required across development for cortical progenitor survival, neural progenitor maintenance, myogenesis, and interdigital cell death, acting via BAF complexes and modulating outputs including p53, Wnt3a, and Fgf8 [PMID:27871306, PMID:28193841, PMID:35198879, PMID:30801883, PMID:30116001].","teleology":[{"year":2013,"claim":"Established an early functional handle on Akirin2 as a transcriptional repressor in cancer, showing it associates with a partner to control a specific target promoter.","evidence":"Reporter assays, ChIP, and antisense knockdown defining an FBI1/Akirin2–14-3-3β complex repressing the BCAM promoter in tumor cells","pmids":["24223164"],"confidence":"Medium","gaps":["Direct mechanism of repression at chromatin not resolved","Generality beyond BCAM/tumor context untested"]},{"year":2014,"claim":"Answered how Akirin2 connects inflammatory signaling to gene activation by identifying it as the physical bridge between NF-κB-associated IκB-ζ and the SWI/SNF remodeler.","evidence":"Reciprocal Co-IP, ChIP, macrophage-specific knockout, and infection/reporter models showing an IκB-ζ–Akirin2–BAF60 complex required for Il6/Il12b induction","pmids":["25107474"],"confidence":"High","gaps":["Structural basis of BAF60 and IκB-ζ binding unknown","Which BAF60 paralog(s) are engaged not fully resolved"]},{"year":2015,"claim":"Extended the SWI/SNF scaffolding role to cell-cycle control, showing Akirin2 is needed for Brg1 recruitment to proliferation-gene promoters.","evidence":"B cell-specific conditional knockout with promoter-level ChIP and in vivo immunization readouts linking Akirin2 to cyclin D/c-Myc expression","pmids":["26041538"],"confidence":"High","gaps":["Whether Akirin2 directly recruits Brg1 or acts indirectly not distinguished","Connection to its proteasome-import role not addressed"]},{"year":2016,"claim":"Demonstrated an essential developmental requirement for Akirin2 in progenitor survival, broadening its role beyond immunity.","evidence":"Emx1-Cre conditional knockout with EdU labeling and in situ hybridization showing massive apoptosis and defective Wnt3a/cortical hem formation","pmids":["27871306"],"confidence":"Medium","gaps":["Molecular target linking Akirin2 to Wnt3a not identified","Whether the phenotype reflects chromatin or proteasome function unknown"]},{"year":2017,"claim":"Placed Akirin2 epistatically within neural and muscle differentiation programs, linking it to BAF complexes and to ERK/NFAT/calcineurin signaling.","evidence":"Xenopus knockdown/epistasis with a BAF53a-containing complex (Sox2/N-tubulin), and porcine satellite-cell overexpression/siRNA with pathway readouts (ERK1/2, NFATc1, calcineurin)","pmids":["28193841","28327665","28223540"],"confidence":"Medium","gaps":["Direct binding to BAF53a-complex not shown in these studies","Signaling links (ERK/NFAT) inferred from pathway readouts, not biochemistry"]},{"year":2019,"claim":"Confirmed an in vivo requirement for Akirin2 in mammalian myogenesis through progenitor survival and differentiation marker expression.","evidence":"Sim1-Cre conditional knockout causing neonatal lethality, muscle agenesis from Pax3+ myoblast apoptosis, and impaired myogenin/MyHC expression in vitro","pmids":["30801883"],"confidence":"Medium","gaps":["Molecular partners mediating myogenic gene control not defined","Cause of myoblast apoptosis not mechanistically linked to a target"]},{"year":2021,"claim":"Resolved a distinct, non-transcriptional core function: AKIRIN2 mediates nuclear import of assembled proteasomes, defining a mechanism for nuclear protein homeostasis.","evidence":"CRISPR screen, Co-IP, intracellular immunostaining, FACS, and live imaging showing homodimeric AKIRIN2 binds 20S proteasomes and re-imports them into daughter nuclei after mitosis","pmids":["34711951"],"confidence":"High","gaps":["Importin identity and assembly mechanism not yet defined","Relationship to the SWI/SNF scaffolding role unresolved"]},{"year":2022,"claim":"Connected loss of nuclear AKIRIN2 function to a cell-survival pathway, placing it upstream of p53-driven death in mature neurons.","evidence":"Neuron-specific conditional knockout with transcriptomics and Trp53-reduction genetic rescue of necroptotic neurodegeneration","pmids":["35198879"],"confidence":"Medium","gaps":["Whether p53 upregulation reflects loss of proteasome import is not directly tested","Mechanistic link between AKIRIN2 loss and necroptosis incomplete"]},{"year":2024,"claim":"Provided the structural and mechanistic basis for proteasome import, showing AKIRIN2 is a multivalent importin-clustering adaptor that is degraded after delivery.","evidence":"Saturation mutagenesis screens, cryo-EM, and biochemical reconstitution defining a wing helix-stabilized interaction, stepwise IPO9/importin recruitment, RanGTP release, and ubiquitin-independent degradation (preprint)","pmids":["bio_10.1101_2024.11.08.622636"],"confidence":"High","gaps":["Peer review pending","How the import function is coordinated with transcriptional roles unknown"]},{"year":null,"claim":"It remains unresolved how AKIRIN2's two functions — proteasome nuclear import and SWI/SNF transcriptional scaffolding — are mechanistically integrated within a single cell and across its many developmental contexts.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No study tests whether developmental phenotypes arise from loss of proteasome import vs. chromatin remodeling","Structural basis of BAF60/IκB-ζ binding undefined","Regulation switching between the two functions unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[2,3,4]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005654","term_label":"nucleoplasm","supporting_discovery_ids":[2,3]}],"pathway":[{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[2,3]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[2,3]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[6,7,9,10]}],"complexes":["SWI/SNF chromatin remodeling complex","20S proteasome (transient import complex)"],"partners":["IPO9","BAF60","NFKBIZ","NFKB1","YWHAB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q53H80","full_name":"Akirin-2","aliases":[],"length_aa":203,"mass_kda":22.5,"function":"Molecular adapter that acts as a bridge between a variety of multiprotein complexes, and which is involved in embryonic development, immunity, myogenesis and brain development (PubMed:34711951). Plays a key role in nuclear protein degradation by promoting import of proteasomes into the nucleus: directly binds to fully assembled 20S proteasomes at one end and to nuclear import receptor IPO9 at the other end, bridging them together and mediating the import of pre-assembled proteasome complexes through the nuclear pore (PubMed:34711951). Involved in innate immunity by regulating the production of interleukin-6 (IL6) downstream of Toll-like receptor (TLR): acts by bridging the NF-kappa-B inhibitor NFKBIZ and the SWI/SNF complex, leading to promote induction of IL6 (By similarity). Also involved in adaptive immunity by promoting B-cell activation (By similarity). Involved in brain development: required for the survival and proliferation of cerebral cortical progenitor cells (By similarity). Involved in myogenesis: required for skeletal muscle formation and skeletal development, possibly by regulating expression of muscle differentiation factors (By similarity). Also plays a role in facilitating interdigital tissue regression during limb development (By similarity)","subcellular_location":"Nucleus; Cytoplasm; Membrane","url":"https://www.uniprot.org/uniprotkb/Q53H80/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/AKIRIN2","classification":"Common Essential","n_dependent_lines":1152,"n_total_lines":1208,"dependency_fraction":0.9536423841059603},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"PSMC4","stoichiometry":0.2},{"gene":"RAN","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/AKIRIN2","total_profiled":1310},"omim":[{"mim_id":"615165","title":"AKIRIN 2; AKIRIN2","url":"https://www.omim.org/entry/615165"},{"mim_id":"615164","title":"AKIRIN 1; AKIRIN1","url":"https://www.omim.org/entry/615164"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/AKIRIN2"},"hgnc":{"alias_symbol":["FLJ10342","dJ486L4.2"],"prev_symbol":["C6orf166"]},"alphafold":{"accession":"Q53H80","domains":[{"cath_id":"1.20.5","chopping":"161-194","consensus_level":"medium","plddt":96.3829,"start":161,"end":194}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q53H80","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q53H80-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q53H80-F1-predicted_aligned_error_v6.png","plddt_mean":65.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=AKIRIN2","jax_strain_url":"https://www.jax.org/strain/search?query=AKIRIN2"},"sequence":{"accession":"Q53H80","fasta_url":"https://rest.uniprot.org/uniprotkb/Q53H80.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q53H80/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q53H80"}},"corpus_meta":[{"pmid":"34711951","id":"PMC_34711951","title":"AKIRIN2 controls the nuclear import of proteasomes in vertebrates.","date":"2021","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/34711951","citation_count":93,"is_preprint":false},{"pmid":"25107474","id":"PMC_25107474","title":"Akirin2 is critical for inducing inflammatory genes by bridging IκB-ζ and the SWI/SNF complex.","date":"2014","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/25107474","citation_count":87,"is_preprint":false},{"pmid":"30886152","id":"PMC_30886152","title":"Akirin2 is modulated by miR-490-3p and facilitates angiogenesis in cholangiocarcinoma through the IL-6/STAT3/VEGFA signaling pathway.","date":"2019","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/30886152","citation_count":38,"is_preprint":false},{"pmid":"26287257","id":"PMC_26287257","title":"Chromatin Remodeling and Transcriptional Control in Innate Immunity: Emergence of Akirin2 as a Novel Player.","date":"2015","source":"Biomolecules","url":"https://pubmed.ncbi.nlm.nih.gov/26287257","citation_count":32,"is_preprint":false},{"pmid":"26041538","id":"PMC_26041538","title":"Essential Function for the Nuclear Protein Akirin2 in B Cell Activation and Humoral Immune Responses.","date":"2015","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/26041538","citation_count":31,"is_preprint":false},{"pmid":"28327665","id":"PMC_28327665","title":"Akirin2 regulates proliferation and differentiation of porcine skeletal muscle satellite cells via ERK1/2 and NFATc1 signaling pathways.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28327665","citation_count":23,"is_preprint":false},{"pmid":"24223164","id":"PMC_24223164","title":"The FBI1/Akirin2 target gene, BCAM, acts as a suppressive oncogene.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24223164","citation_count":22,"is_preprint":false},{"pmid":"27871306","id":"PMC_27871306","title":"Akirin2 is essential for the formation of the cerebral cortex.","date":"2016","source":"Neural development","url":"https://pubmed.ncbi.nlm.nih.gov/27871306","citation_count":17,"is_preprint":false},{"pmid":"24468084","id":"PMC_24468084","title":"FBI1/Akirin2 promotes tumorigenicity and metastasis of Lewis lung carcinoma cells.","date":"2014","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/24468084","citation_count":16,"is_preprint":false},{"pmid":"22537061","id":"PMC_22537061","title":"Molecular cloning, tissue distribution, and functional analysis of porcine Akirin2.","date":"2012","source":"Animal biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/22537061","citation_count":16,"is_preprint":false},{"pmid":"26036627","id":"PMC_26036627","title":"Down regulation of Akirin-2 increases chemosensitivity in human glioblastomas more efficiently than Twist-1.","date":"2015","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/26036627","citation_count":16,"is_preprint":false},{"pmid":"28193841","id":"PMC_28193841","title":"Dual roles of Akirin2 protein during Xenopus neural development.","date":"2017","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/28193841","citation_count":15,"is_preprint":false},{"pmid":"29685038","id":"PMC_29685038","title":"Arginine Promotes Slow Myosin Heavy Chain Expression via Akirin2 and the AMP-Activated Protein Kinase Signaling Pathway in Porcine Skeletal Muscle Satellite Cells.","date":"2018","source":"Journal of agricultural and food chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/29685038","citation_count":15,"is_preprint":false},{"pmid":"25284180","id":"PMC_25284180","title":"The identification of the first molluscan Akirin2 with immune defense function in the Hong Kong oyster Crassostrea hongkongensis.","date":"2014","source":"Fish & shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/25284180","citation_count":15,"is_preprint":false},{"pmid":"29945498","id":"PMC_29945498","title":"Expression analysis of Akirin-2, NFκB-p65 and β-catenin proteins in imatinib resistance of chronic myeloid leukemia.","date":"2018","source":"Hematology (Amsterdam, Netherlands)","url":"https://pubmed.ncbi.nlm.nih.gov/29945498","citation_count":14,"is_preprint":false},{"pmid":"24389387","id":"PMC_24389387","title":"Identification and molecular characterization of an Akirin2 homolog in Chinese loach (Paramisgurnus dabryanus).","date":"2014","source":"Fish & shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/24389387","citation_count":14,"is_preprint":false},{"pmid":"30116001","id":"PMC_30116001","title":"An essential role for the nuclear protein Akirin2 in mouse limb interdigital tissue regression.","date":"2018","source":"Scientific 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& shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/33259930","citation_count":10,"is_preprint":false},{"pmid":"25239665","id":"PMC_25239665","title":"Molecular cloning, sequence analysis and tissue-specific expression of Akirin2 gene in Tianfu goat.","date":"2014","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/25239665","citation_count":9,"is_preprint":false},{"pmid":"25686036","id":"PMC_25686036","title":"Effect of porcine Akirin2 on skeletal myosin heavy chain isoform expression.","date":"2015","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/25686036","citation_count":9,"is_preprint":false},{"pmid":"27590857","id":"PMC_27590857","title":"Akirin2 could promote the proliferation but not the differentiation of duck myoblasts via the activation of the mTOR/p70S6K signaling pathway.","date":"2016","source":"The international journal of biochemistry & cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27590857","citation_count":8,"is_preprint":false},{"pmid":"35198879","id":"PMC_35198879","title":"p53-mediated neurodegeneration in the absence of the nuclear protein Akirin2.","date":"2022","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/35198879","citation_count":7,"is_preprint":false},{"pmid":"30801883","id":"PMC_30801883","title":"A critical role for the nuclear protein Akirin2 in the formation of mammalian muscle in vivo.","date":"2019","source":"Genesis (New York, N.Y. : 2000)","url":"https://pubmed.ncbi.nlm.nih.gov/30801883","citation_count":7,"is_preprint":false},{"pmid":"29144179","id":"PMC_29144179","title":"Effects of Active Immunization Against Akirin2 on Muscle Fiber-type Composition in Pigs.","date":"2017","source":"Animal biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/29144179","citation_count":7,"is_preprint":false},{"pmid":"21858694","id":"PMC_21858694","title":"Molecular cloning, sequence characterization, and tissue expression analysis of Hi-Line Brown chicken Akirin2.","date":"2011","source":"The protein journal","url":"https://pubmed.ncbi.nlm.nih.gov/21858694","citation_count":6,"is_preprint":false},{"pmid":"28223540","id":"PMC_28223540","title":"Akirin2 promotes slow myosin heavy chain expression by CaN/NFATc1 signaling in porcine skeletal muscle satellite cells.","date":"2017","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/28223540","citation_count":5,"is_preprint":false},{"pmid":"39267282","id":"PMC_39267282","title":"Transcranial direct current stimulation enhances the protective effect of isoflurane preconditioning on cerebral ischemia/reperfusion injury: A new mechanism associated with the nuclear protein Akirin2.","date":"2024","source":"CNS neuroscience & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/39267282","citation_count":5,"is_preprint":false},{"pmid":"34995507","id":"PMC_34995507","title":"Nuclear destruction: A suicide mission by AKIRIN2 brings intact proteasomes into the nucleus.","date":"2022","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/34995507","citation_count":4,"is_preprint":false},{"pmid":"26782392","id":"PMC_26782392","title":"Akirin2 expression in response to vaccine-induced immunity in chicken.","date":"2015","source":"Genetics and molecular research : GMR","url":"https://pubmed.ncbi.nlm.nih.gov/26782392","citation_count":4,"is_preprint":false},{"pmid":"25098451","id":"PMC_25098451","title":"Cloning and expression pattern of akirin2 gene in broiler.","date":"2014","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/25098451","citation_count":3,"is_preprint":false},{"pmid":"28605346","id":"PMC_28605346","title":"Akirin2-Mediated Transcriptional Control by Recruiting SWI/SNF Complex in B Cells.","date":"2016","source":"Critical reviews in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/28605346","citation_count":3,"is_preprint":false},{"pmid":"38685443","id":"PMC_38685443","title":"Akirin2 enhances antibacterial ability via interacting with 14-3-3ζ in V. splendidus-challenged Apostichopus japonicus.","date":"2024","source":"Fish & shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/38685443","citation_count":3,"is_preprint":false},{"pmid":"32779549","id":"PMC_32779549","title":"Distribution of the variant at AKIRIN2: c.*188G > A in Chinese cattle.","date":"2020","source":"Animal biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/32779549","citation_count":1,"is_preprint":false},{"pmid":"41192674","id":"PMC_41192674","title":"Akirin2 regulates IL-6 expression and contributes to immune defense in silver pomfret (Pampus argenteus).","date":"2025","source":"Fish & shellfish immunology","url":"https://pubmed.ncbi.nlm.nih.gov/41192674","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2024.11.08.622636","title":"A multivalent adaptor mechanism drives the nuclear import of proteasomes","date":"2024-11-08","source":"bioRxiv","url":"https://doi.org/10.1101/2024.11.08.622636","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":18743,"output_tokens":3856,"usd":0.057035,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11723,"output_tokens":3536,"usd":0.073508,"stage2_stop_reason":"end_turn"},"total_usd":0.130543,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"AKIRIN2 forms homodimers that directly bind to fully assembled 20S proteasomes and mediates their nuclear import in vertebrates. During mitosis, proteasomes are excluded from condensing chromatin and re-imported into newly formed daughter nuclei in an AKIRIN2-dependent process. Cells lacking AKIRIN2 become devoid of nuclear proteasomes, causing accumulation of MYC and other nuclear proteins.\",\n      \"method\": \"CRISPR screen, Co-IP, intracellular immunostaining, FACS, live cell imaging, biochemical fractionation\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct binding demonstrated biochemically, functional consequence of loss established by multiple orthogonal methods including CRISPR screen, Co-IP, and live imaging\",\n      \"pmids\": [\"34711951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"AKIRIN2 acts as a scaffold/adaptor protein that coordinates stepwise assembly of an importin cluster around the proteasome. A wing helix in a disordered region of AKIRIN2 stabilizes proteasome interactions. AKIRIN2 homodimers recruit importin IPO9, which facilitates binding of a second AKIRIN2 homodimer that recruits additional importins, creating a multivalent assembly that amplifies nuclear localization signals for efficient proteasome translocation. Inside the nucleus, RanGTP dissociates importins, and AKIRIN2 is degraded by the proteasome in a ubiquitin-independent manner.\",\n      \"method\": \"Protein-wide saturation mutagenesis screens (FACS- and microscopy-based), cryo-EM, biochemical reconstitution\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure combined with saturation mutagenesis and biochemical reconstitution; multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"bio_10.1101_2024.11.08.622636\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Akirin2 bridges the NF-κB pathway and the SWI/SNF chromatin remodeling complex by interacting with BAF60 proteins and IκB-ζ (which forms a complex with NF-κB p50). This IκB-ζ–Akirin2–BAF60 complex is essential for TLR-, RIG-I-, and Listeria-mediated induction of proinflammatory genes (Il6, Il12b) in macrophages. Akirin2 and IκB-ζ mutually depend on each other for recruitment to the Il6 promoter.\",\n      \"method\": \"Co-immunoprecipitation, chromatin immunoprecipitation, macrophage-specific knockout, reporter assays, infection models\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, ChIP, genetic KO with specific phenotypic readouts, multiple stimuli tested, independently replicated across related studies\",\n      \"pmids\": [\"25107474\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Akirin2 is required for B cell cycle progression and humoral immune responses by controlling the SWI/SNF complex. Akirin2-deficient B cells show defective expression of cyclin D and c-Myc, and impaired Brg1 recruitment to Myc and Ccnd2 promoters. B cell-specific knockout leads to decreased follicular and peritoneal B-1 cell numbers, defective proliferation, and apoptosis in response to TLR ligands, CD40, and BCR stimulation.\",\n      \"method\": \"B cell-specific conditional knockout (Cd19-Cre), chromatin immunoprecipitation, flow cytometry, in vivo immunization\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional KO with specific promoter-level ChIP evidence and multiple orthogonal readouts in vivo and in vitro\",\n      \"pmids\": [\"26041538\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"FBI1/Akirin2 forms a complex with 14-3-3β that acts as a transcriptional repressor binding to the BCAM promoter, suppressing BCAM expression and thereby promoting tumorigenicity and metastasis.\",\n      \"method\": \"Luciferase reporter assay, chromatin immunoprecipitation, antisense knockdown, in vivo tumor assay\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and reporter assays confirm promoter binding, functional KD validated in vivo, single lab\",\n      \"pmids\": [\"24223164\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Akirin2 regulates proliferation and differentiation of porcine skeletal muscle satellite cells through ERK1/2 and NFATc1 signaling pathways, as demonstrated by overexpression and siRNA knockdown experiments.\",\n      \"method\": \"Overexpression and siRNA knockdown, western blot, cell proliferation/differentiation assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — gain- and loss-of-function with pathway readouts, single lab, no direct binding or structural data\",\n      \"pmids\": [\"28327665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Akirin2 is required for early cortical progenitor survival and proliferation during cerebral cortex formation. Loss of Akirin2 in cortical progenitors causes massive apoptosis starting at E10, failure of normal proliferation, and defective Wnt3a signaling/cortical hem formation.\",\n      \"method\": \"Cortex-restricted conditional knockout (Emx1-Cre), EdU labeling, in situ hybridization, immunohistochemistry\",\n      \"journal\": \"Neural development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with specific cellular and molecular phenotypes, EdU and ISH, single lab\",\n      \"pmids\": [\"27871306\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Akirin2 in Xenopus neural development acts upstream of BAF53a-containing BAF complex to maintain neural progenitor state (regulating Sox2 expression antagonistically to Geminin), and also acts upstream of NeuroD and in parallel with Ngnr1 for terminal neuronal differentiation (regulating N-tubulin expression).\",\n      \"method\": \"Xenopus knockdown, epistasis analysis, rescue experiments, in situ hybridization\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis established by double-knockdown rescue in Xenopus, single lab\",\n      \"pmids\": [\"28193841\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Akirin2 loss in mature cortical neurons causes progressive neurodegeneration via necroptosis, associated with upregulation of p53 (Trp53) target genes. Genetic reduction of Trp53 rescued neurodegeneration in Akirin2-null neurons, placing Akirin2 upstream of p53-mediated cell death pathways.\",\n      \"method\": \"Neuron-specific conditional knockout, transcriptomics, genetic epistasis (Trp53 reduction rescue), histology\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with transcriptomic analysis and genetic rescue establishing pathway placement, single lab\",\n      \"pmids\": [\"35198879\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Akirin2 is required for mammalian myogenesis in vivo; loss in somitic muscle precursors via Sim1-Cre leads to neonatal lethality, absence of forelimb/intercostal/diaphragm muscles due to apoptosis of Pax3-positive myoblasts, and impaired expression of myogenin and myosin heavy chain during muscle cell differentiation in vitro.\",\n      \"method\": \"Conditional knockout (Sim1-Cre), immunohistochemistry, in vitro differentiation assays, western blot\",\n      \"journal\": \"Genesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with molecular marker analysis in vivo and in vitro, single lab\",\n      \"pmids\": [\"30801883\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Akirin2 is required for interdigital tissue regression in the mouse limb; knockout in limb epithelium leads to loss of interdigital cell death, increased cell proliferation, and soft-tissue syndactyly. This is associated with perdurance of Fgf8 expression, implicating Akirin2 in downregulation of Fgf8 from the apical ectodermal ridge.\",\n      \"method\": \"Conditional knockout in limb epithelium, immunohistochemistry, in situ hybridization\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with molecular marker evidence, pathway placement via Fgf8 expression analysis, single lab\",\n      \"pmids\": [\"30116001\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Akirin2 promotes slow MyHC I expression via calcineurin (CaN)/NFATc1 signaling pathway in porcine skeletal muscle satellite cells; knockdown of Akirin2 decreases CaN activity and NFATc1 expression, while overexpression has the opposite effect, and inhibition of CaN or NFATc1 knockdown blocks Akirin2 overexpression-induced upregulation of MyHC I.\",\n      \"method\": \"siRNA knockdown, overexpression, pharmacological inhibition, western blot, qPCR\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — pathway placement by genetic epistasis (inhibitor/siRNA rescue), single lab, no direct binding data\",\n      \"pmids\": [\"28223540\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Duck Akirin2 promotes myoblast proliferation (but not differentiation) via activation of the mTOR/p70S6K signaling pathway; rapamycin blocks Akirin2-induced increases in cell viability, mTOR and p70S6K mRNA, and phospho-mTOR/phospho-p70S6K protein levels.\",\n      \"method\": \"Overexpression, pharmacological inhibition (rapamycin), flow cytometry, western blot\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, pharmacological inhibitor only, no direct binding or genetic epistasis\",\n      \"pmids\": [\"27590857\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"AjAkirin2 (sea cucumber ortholog) directly interacts with Aj14-3-3ζ as demonstrated by GST-pulldown and co-IP assays. AjAkirin2 positively regulates Aj14-3-3ζ expression, and knockdown of either protein increases intracellular bacterial load and suppresses NF-κB signaling pathway genes and inflammatory cytokines.\",\n      \"method\": \"GST-pulldown, co-immunoprecipitation, RNAi knockdown, bacterial load assay, qPCR\",\n      \"journal\": \"Fish & shellfish immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding confirmed by two orthogonal pulldown methods, functional consequence of KD demonstrated, invertebrate ortholog\",\n      \"pmids\": [\"38685443\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Akirin2 induces angiogenesis in cholangiocarcinoma by increasing VEGFA expression through activation of the IL-6/STAT3 signaling pathway, and promotes EMT-associated migration and invasion. miR-490-3p negatively regulates Akirin2 expression at the post-transcriptional level via its 3'-UTR.\",\n      \"method\": \"Lentiviral knockdown/overexpression, luciferase reporter assay (3'-UTR), in vivo tumor model, western blot\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pathway placement by KD/OE without direct binding evidence, single lab, cancer cell line context\",\n      \"pmids\": [\"30886152\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"FBI1/Akirin2 downregulation in Lewis lung carcinoma cells decreased anchorage-independent growth and reduced tumor growth and metastasis in vivo, indicating FBI1/Akirin2 overexpression is required for LLC1 tumor growth and metastasis.\",\n      \"method\": \"Antisense knockdown, in vitro anchorage-independent growth assay, in vivo nude mouse tumor assay\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — KD with phenotypic readout, no molecular mechanism established beyond the 14-3-3β complex described in companion paper, single lab\",\n      \"pmids\": [\"24468084\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"AKIRIN2 is a conserved nuclear scaffold protein with two key mechanistic roles: (1) it forms homodimers that directly bind fully assembled 20S proteasomes and recruit importins (including IPO9) via a multivalent adaptor mechanism to drive nuclear import of proteasomes in vertebrates, a process essential for nuclear protein homeostasis; and (2) it bridges NF-κB signaling (via IκB-ζ/p50) to the SWI/SNF chromatin remodeling complex (via BAF60 proteins) to enable transcriptional activation of proinflammatory genes, B cell cycle progression, and chromatin remodeling during development and immunity.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"AKIRIN2 is a conserved nuclear protein that functions dually as an importin-coupled adaptor for proteasome nuclear import and as a transcriptional scaffold bridging signaling to chromatin remodeling [#0, #2]. As a homodimer, it binds directly to fully assembled 20S proteasomes and is required for their nuclear import; cells lacking AKIRIN2 lose nuclear proteasomes and accumulate nuclear substrates such as MYC, and during mitosis AKIRIN2 re-imports proteasomes into newly formed daughter nuclei [#0]. Mechanistically, a wing helix within a disordered region stabilizes the proteasome interaction, and AKIRIN2 homodimers nucleate stepwise recruitment of importins (including IPO9) into a multivalent cluster that amplifies nuclear localization signals for efficient translocation, after which RanGTP releases the importins and AKIRIN2 is degraded by the proteasome in a ubiquitin-independent manner [#1]. In its transcriptional role, AKIRIN2 links the NF-\\u03baB pathway to the SWI/SNF complex by interacting with BAF60 proteins and with I\\u03baB-\\u03b6 (in complex with NF-\\u03baB p50), an interaction required for induction of proinflammatory genes such as Il6 and Il12b in macrophages and for Brg1 recruitment to Myc and Ccnd2 promoters driving B cell proliferation [#2, #3]. Consistent with a chromatin-remodeling role acting upstream of progenitor maintenance and cell-survival programs, AKIRIN2 is required across development for cortical progenitor survival, neural progenitor maintenance, myogenesis, and interdigital cell death, acting via BAF complexes and modulating outputs including p53, Wnt3a, and Fgf8 [#6, #7, #8, #9, #10].\",\n  \"teleology\": [\n    {\n      \"year\": 2013,\n      \"claim\": \"Established an early functional handle on Akirin2 as a transcriptional repressor in cancer, showing it associates with a partner to control a specific target promoter.\",\n      \"evidence\": \"Reporter assays, ChIP, and antisense knockdown defining an FBI1/Akirin2\\u201314-3-3\\u03b2 complex repressing the BCAM promoter in tumor cells\",\n      \"pmids\": [\"24223164\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct mechanism of repression at chromatin not resolved\", \"Generality beyond BCAM/tumor context untested\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Answered how Akirin2 connects inflammatory signaling to gene activation by identifying it as the physical bridge between NF-\\u03baB-associated I\\u03baB-\\u03b6 and the SWI/SNF remodeler.\",\n      \"evidence\": \"Reciprocal Co-IP, ChIP, macrophage-specific knockout, and infection/reporter models showing an I\\u03baB-\\u03b6\\u2013Akirin2\\u2013BAF60 complex required for Il6/Il12b induction\",\n      \"pmids\": [\"25107474\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of BAF60 and I\\u03baB-\\u03b6 binding unknown\", \"Which BAF60 paralog(s) are engaged not fully resolved\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Extended the SWI/SNF scaffolding role to cell-cycle control, showing Akirin2 is needed for Brg1 recruitment to proliferation-gene promoters.\",\n      \"evidence\": \"B cell-specific conditional knockout with promoter-level ChIP and in vivo immunization readouts linking Akirin2 to cyclin D/c-Myc expression\",\n      \"pmids\": [\"26041538\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Akirin2 directly recruits Brg1 or acts indirectly not distinguished\", \"Connection to its proteasome-import role not addressed\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrated an essential developmental requirement for Akirin2 in progenitor survival, broadening its role beyond immunity.\",\n      \"evidence\": \"Emx1-Cre conditional knockout with EdU labeling and in situ hybridization showing massive apoptosis and defective Wnt3a/cortical hem formation\",\n      \"pmids\": [\"27871306\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular target linking Akirin2 to Wnt3a not identified\", \"Whether the phenotype reflects chromatin or proteasome function unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Placed Akirin2 epistatically within neural and muscle differentiation programs, linking it to BAF complexes and to ERK/NFAT/calcineurin signaling.\",\n      \"evidence\": \"Xenopus knockdown/epistasis with a BAF53a-containing complex (Sox2/N-tubulin), and porcine satellite-cell overexpression/siRNA with pathway readouts (ERK1/2, NFATc1, calcineurin)\",\n      \"pmids\": [\"28193841\", \"28327665\", \"28223540\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct binding to BAF53a-complex not shown in these studies\", \"Signaling links (ERK/NFAT) inferred from pathway readouts, not biochemistry\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Confirmed an in vivo requirement for Akirin2 in mammalian myogenesis through progenitor survival and differentiation marker expression.\",\n      \"evidence\": \"Sim1-Cre conditional knockout causing neonatal lethality, muscle agenesis from Pax3+ myoblast apoptosis, and impaired myogenin/MyHC expression in vitro\",\n      \"pmids\": [\"30801883\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular partners mediating myogenic gene control not defined\", \"Cause of myoblast apoptosis not mechanistically linked to a target\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Resolved a distinct, non-transcriptional core function: AKIRIN2 mediates nuclear import of assembled proteasomes, defining a mechanism for nuclear protein homeostasis.\",\n      \"evidence\": \"CRISPR screen, Co-IP, intracellular immunostaining, FACS, and live imaging showing homodimeric AKIRIN2 binds 20S proteasomes and re-imports them into daughter nuclei after mitosis\",\n      \"pmids\": [\"34711951\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Importin identity and assembly mechanism not yet defined\", \"Relationship to the SWI/SNF scaffolding role unresolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Connected loss of nuclear AKIRIN2 function to a cell-survival pathway, placing it upstream of p53-driven death in mature neurons.\",\n      \"evidence\": \"Neuron-specific conditional knockout with transcriptomics and Trp53-reduction genetic rescue of necroptotic neurodegeneration\",\n      \"pmids\": [\"35198879\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether p53 upregulation reflects loss of proteasome import is not directly tested\", \"Mechanistic link between AKIRIN2 loss and necroptosis incomplete\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Provided the structural and mechanistic basis for proteasome import, showing AKIRIN2 is a multivalent importin-clustering adaptor that is degraded after delivery.\",\n      \"evidence\": \"Saturation mutagenesis screens, cryo-EM, and biochemical reconstitution defining a wing helix-stabilized interaction, stepwise IPO9/importin recruitment, RanGTP release, and ubiquitin-independent degradation (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.11.08.622636\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Peer review pending\", \"How the import function is coordinated with transcriptional roles unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how AKIRIN2's two functions \\u2014 proteasome nuclear import and SWI/SNF transcriptional scaffolding \\u2014 are mechanistically integrated within a single cell and across its many developmental contexts.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No study tests whether developmental phenotypes arise from loss of proteasome import vs. chromatin remodeling\", \"Structural basis of BAF60/I\\u03baB-\\u03b6 binding undefined\", \"Regulation switching between the two functions unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [2, 3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005654\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [2, 3]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [6, 7, 9, 10]}\n    ],\n    \"complexes\": [\"SWI/SNF chromatin remodeling complex\", \"20S proteasome (transient import complex)\"],\n    \"partners\": [\"IPO9\", \"BAF60\", \"NFKBIZ\", \"NFKB1\", \"YWHAB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}