Affinage

CWC22

Pre-mRNA-splicing factor CWC22 homolog · UniProt Q9HCG8

Length
908 aa
Mass
105.5 kDa
Annotated
2026-06-09
42 papers in source corpus 11 papers cited in narrative 11 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/7 claims corpus-supported (86%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CWC22 is a conserved spliceosomal protein that couples pre-mRNA splicing to assembly of the exon junction complex (EJC) (PMID:22959432, PMID:22961380). Its MIF4G domain binds the DEAD-box helicase eIF4A3 directly, and a 2.0 Å crystal structure shows that this interaction clamps the two RecA domains of eIF4A3 in diametrically opposite orientations incompatible with the active state, holding the helicase in an RNA-binding-incompetent conformation until CWC22 escorts it to the spliceosome where EJC deposition is triggered (PMID:22961380, PMID:24218557). These two activities are separable: an eIF4A3-binding-deficient CWC22 retains splicing function but fails to deposit EJCs, while the protein core suffices for both and a C-terminal domain enhances spliceosomal interaction (PMID:23236153, PMID:25870412). On the activated (Bact) spliceosome CWC22 forms a stable heterodimer with CWC27 that together constitute a landing platform for eIF4A3, structurally compatible with Bact but not C complex, positioning eIF4A3 for recruitment prior to catalytic remodeling (PMID:32329775). In yeast, Cwc22 is required for the Prp2-dependent splicing step, enabling Prp2 to displace the U2 components SF3a and SF3b upon ATP hydrolysis (PMID:20956557). Loss of CWC22 globally impairs splicing, disrupts EJC deposition, and attenuates nonsense-mediated decay (PMID:23236153, PMID:25870412), and in mitotic cancer cells causes spindle assembly checkpoint failure through downregulation of BubR1 and accumulation of inactive Tyr15-phosphorylated CDK1, leading to mitotic slippage (PMID:41534835). CWC22 has also been implicated in nociceptive signaling, where it is upregulated in diabetic and inflammatory pain states and regulates Spp1 splicing (PMID:28250049, PMID:37838283).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2010 High

    Established Cwc22 as a splicing factor with a specific mechanistic role, answering where in the splicing cycle it acts: it is required for the Prp2-dependent step that releases SF3a/SF3b.

    Evidence In vivo and in vitro splicing assays with spliceosome fractionation and Prp2 functional assays in yeast

    PMID:20956557

    Open questions at the time
    • Did not link Cwc22 to EJC assembly
    • Molecular basis of how Cwc22 enables Prp2-dependent SF3a/b release not resolved
  2. 2012 High

    Resolved how splicing is coupled to EJC assembly by showing CWC22 directly binds eIF4A3 via its MIF4G domain and escorts the helicase to the spliceosome while blocking its premature RNA binding.

    Evidence Co-IP, recombinant in vitro binding, interface mutagenesis, in vitro splicing/deposition assays, and RNAi rescue in Drosophila and human cells across independent labs

    PMID:22959432 PMID:22961380 PMID:23236153

    Open questions at the time
    • Structural basis of the inhibitory binding mode not yet defined
    • Did not separate splicing from EJC-deposition activities cleanly until mutant analysis
  3. 2013 High

    Provided the structural mechanism for eIF4A3 inhibition, explaining how CWC22 prevents nonspecific RNA binding by locking both RecA domains in an inactive orientation.

    Evidence X-ray crystallography at 2.0 Å of the eIF4AIII–CWC22 MIF4G complex

    PMID:24218557

    Open questions at the time
    • Does not capture the conformational transition that activates eIF4A3 on the spliceosome
    • No structure of CWC22 within the assembled spliceosome
  4. 2015 High

    Demonstrated that CWC22's splicing and EJC-assembly functions are genetically separable, defining the minimal core and a spliceosome-enhancing C-terminal region.

    Evidence Domain deletion, eIF4A3-binding-deficient mutants, RNAi depletion, and high-throughput RNA-seq in human cells

    PMID:25870412

    Open questions at the time
    • Mechanism by which the C-terminal domain enhances spliceosome interaction undefined
    • Spliceosomal contacts beyond eIF4A3 not mapped
  5. 2020 High

    Identified CWC27 as a stable CWC22 partner and showed the two form a structural landing platform that recruits eIF4A3 at the Bact stage before C-complex conversion.

    Evidence Reciprocal co-IP, 3 Å crystal structure of the eIF4A3/CWC22/CWC27 ternary complex, modeling against spliceosome structures, and siRNA RNA-seq in retinal cells

    PMID:32329775

    Open questions at the time
    • Dynamics of platform disassembly during Bact-to-C transition not observed
    • Whether CWC27 contributes catalytically or only structurally unresolved
  6. 2017 Medium

    Extended CWC22 beyond core splicing biology into disease physiology, showing its upregulation impairs sensory neuron function in diabetic nerves.

    Evidence Protein quantification in DRG, in vitro siRNA neurite outgrowth assay, and in vivo axonal siRNA delivery with sensory behavioral testing

    PMID:28250049

    Open questions at the time
    • Molecular splicing targets driving the neuronal phenotype not identified
    • Link to canonical EJC/splicing function not established
  7. 2017 Medium

    Showed evolutionary plasticity of CWC22 by demonstrating that a CWC22 duplicate became the housefly male-determining factor controlling sex-specific splicing.

    Evidence Genetic identification, targeted disruption with sex-reversal phenotype, and downstream transformer/doublesex splicing analysis

    PMID:28495751

    Open questions at the time
    • Mechanism distinguishing the neofunctionalized paralog from ancestral CWC22 not detailed
    • Relevance to mammalian CWC22 function indirect
  8. 2023 Medium

    Connected CWC22-dependent alternative splicing to a physiological output, identifying Spp1 variant 4 as a required mediator of CWC22-driven nociception.

    Evidence Lentiviral knockdown/overexpression in spinal dorsal horn, behavioral pain tests, RNA-seq, and splicing assays

    PMID:37838283

    Open questions at the time
    • How CWC22 selects the Spp1 V4 splice choice mechanistically unclear
    • Single-lab, single-pathway readout
  9. 2026 Medium

    Revealed a mitotic role for CWC22, showing it is required for spindle assembly checkpoint function by sustaining BubR1 expression and CDK1 activity.

    Evidence siRNA knockdown with flow cytometry, live-cell imaging, RNA-seq, and rescue by BubR1 overexpression, cyclin B1 overexpression, and Wee1 inhibition in cancer cells

    PMID:41534835

    Open questions at the time
    • Whether BubR1/CDK1 effects are direct splicing consequences not established
    • Generalizability beyond the cancer cell models tested unknown

Open questions

Synthesis pass · forward-looking unresolved questions
  • How CWC22's global splicing/EJC activity is selectively channeled into distinct tissue-specific outcomes (sensory neuron function, nociception, mitotic checkpoint) remains unresolved.
  • No unified mechanism linking core EJC function to the divergent disease phenotypes
  • Direct splicing targets underlying each phenotype largely unmapped

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 4 GO:0098772 molecular function regulator activity 2
Localization
GO:0005634 nucleus 3
Pathway
R-HSA-8953854 Metabolism of RNA 4 R-HSA-1640170 Cell Cycle 1
Partners
CWC27EIF4A3
Complex memberships
CWC22–CWC27 heterodimerexon junction complexspliceosome

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2012 CWC22 is an essential splicing factor required for EJC assembly; its MIF4G domain directly interacts with the EJC core protein eIF4A3 to initiate EJC assembly. Mutations in eIF4A3 that abolish CWC22 binding prevent splicing-dependent EJC deposition but not splicing-independent recombinant EJC core assembly. Co-immunoprecipitation, in vitro binding assays, mutagenesis of eIF4A3 interface residues, RNAi depletion with rescue experiments, in vitro splicing assays Cell reports High 22959432
2012 Human CWC22 directly contacts eIF4A3 and prevents it from binding RNA in the free state, then escorts eIF4A3 to spliceosomes before spliceosome remodeling, facilitating eIF4A3 incorporation into the EJC on mature mRNA. Recombinant protein binding assays, in vitro splicing assays, co-immunoprecipitation, knockdown in vivo (Drosophila and human cells) Nature structural & molecular biology High 22961380
2012 Human CWC22 directly interacts with eIF4A3 in vitro and in vivo; interface mutations (hCWC22 G168Y) disrupt association and exacerbate the defect in splicing-dependent eIF4A3 deposition without inhibiting splicing itself, establishing a specific role for CWC22 in EJC deposition distinct from its splicing role. CWC22 depletion causes a splicing defect and impairs NMD through failure to deposit EJCs. In vitro binding assays, in vivo co-immunoprecipitation, site-directed mutagenesis at predicted interface, in vitro splicing/deposition assays, in vivo RNAi depletion with mRNA level analysis Proceedings of the National Academy of Sciences of the United States of America High 23236153
2013 Crystal structure (2.0 Å) of human eIF4AIII bound to the MIF4G domain of CWC22 reveals that CWC22 MIF4G binds both RecA domains of eIF4AIII in an inhibitory mode: the RNA-binding and ATP-binding motifs of the two RecA domains are positioned in diametrically opposite orientations (incompatible with the active state), mechanistically explaining how CWC22 prevents eIF4AIII from nonspecifically binding RNA prior to spliceosomal delivery. X-ray crystallography at 2.0 Å resolution Proceedings of the National Academy of Sciences of the United States of America High 24218557
2010 Yeast Cwc22 is required for pre-mRNA splicing in vivo and in vitro but is not a stable NTC component and is not required for spliceosome activation. Cwc22 associates with the spliceosome prior to catalytic steps and remains throughout the reaction; its stable association requires NTC but is independent of Prp2. Cwc22 is essential for Prp2 function in promoting release of U2 components SF3a and SF3b: in the absence of Cwc22, Prp2 binds but is released upon ATP hydrolysis without displacing SF3a/b. In vivo splicing assays, in vitro splicing assays, spliceosome pull-down/fractionation, ATPase/functional assays with Prp2 Molecular and cellular biology High 20956557
2015 The core of CWC22 is sufficient to mediate both pre-mRNA splicing and EJC assembly, but these two functions can be functionally uncoupled using an eIF4A3-binding-deficient CWC22 mutant. A C-terminal domain of CWC22 enhances its spliceosomal interaction. CWC22 depletion causes global pre-mRNA splicing defects across hundreds of genes as shown by high-throughput RNA-seq. Domain deletion analysis, eIF4A3-binding-deficient mutants, RNAi depletion, high-throughput RNA-seq, in vivo splicing and EJC assembly assays Nucleic acids research High 25870412
2020 CWC22 forms a stable heterodimer with the splicing factor CWC27; the crystal structure (3 Å) of the eIF4A3/CWC22/CWC27 ternary complex reveals that CWC27 and CWC22 together form a landing platform for eIF4A3 on the Bact spliceosome complex. The structure is compatible with Bact but not C complex (a CWC27 loop would clash with EJC subunit Y14), suggesting CWC27/CWC22 facilitate eIF4A3 recruitment before its conversion to C complex. Knockdown of either CWC27 or CWC22 affects the same gene sets in retinal cells. Co-immunoprecipitation (CWC27 pulldown identifying CWC22 as major partner), X-ray crystallography at 3 Å, structural modeling against published spliceosome structures, siRNA knockdown with RNA-seq Nucleic acids research High 32329775
2017 CWC22 protein is aberrantly upregulated in diabetic dorsal root ganglia and impairs neuronal function; knockdown of CWC22 in vitro enhances sensory neuron neurite outgrowth, and axonal siRNA delivery to knock down CWC22 in diabetic nerves in vivo improves aspects of sensory function. Immunohistochemistry/protein quantification in DRG, in vitro siRNA knockdown with neurite outgrowth assay, in vivo axonal siRNA delivery with sensory behavioral testing Disease models & mechanisms Medium 28250049
2023 Spinal CWC22 is upregulated after inflammatory pain induction; knockdown of spinal CWC22 reverses thermal hyperalgesia and mechanical allodynia, while CWC22 overexpression induces pain in naïve mice. CWC22 mediates alternative splicing of Spp1, and specifically the Spp1 splicing variant 4 (Spp1 V4) is required for CWC22-dependent nociceptive regulation. Lentivirus-mediated knockdown and overexpression in spinal dorsal horn, behavioral pain tests, transcriptome/genome analysis (RNA-seq), molecular biological assays for splicing Neuroscience Medium 37838283
2026 Knockdown of CWC22 in cancer cells causes mitotic slippage (premature mitotic exit) by downregulating SAC-regulatory genes including BubR1 and leading to accumulation of inactive CDK1 (phosphorylated at Tyr15) and cyclin B1 degradation in mitosis. Simultaneous cyclin B1 overexpression and Wee1 blockade, or BubR1 overexpression, mitigates the shortened mitotic duration caused by CWC22 knockdown, establishing CWC22 as required for spindle assembly checkpoint function via maintenance of BubR1 expression and CDK1 activity. siRNA knockdown, cell cycle analysis (flow cytometry), live-cell imaging, RNA-seq, cyclin B1 overexpression, Wee1 inhibitor treatment, BubR1 overexpression rescue The Journal of biological chemistry Medium 41534835
2017 Mdmd, the housefly male-determining M-factor, originated from a duplication of the spliceosomal factor gene CWC22 (nucampholin/Cwc22). Targeted disruption of Mdmd results in complete sex reversal to fertile females via a shift from male to female splicing of transformer and doublesex, demonstrating that CWC22 paralogs can acquire neofunctionalized roles in sex determination through gene duplication. Genetic identification, targeted gene disruption (CRISPR/RNAi), sex-reversal phenotype analysis, downstream gene expression assays Science (New York, N.Y.) Medium 28495751

Source papers

Stage 0 corpus · 42 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2017 Male sex in houseflies is determined by Mdmd, a paralog of the generic splice factor gene CWC22. Science (New York, N.Y.) 107 28495751
2019 Chemical, Structural, and Electronic Aspects of Formation and Degradation Behavior on Different Length Scales of Ni-Rich NCM and Li-Rich HE-NCM Cathode Materials in Li-Ion Batteries. Advanced materials (Deerfield Beach, Fla.) 103 31012176
2012 CWC22 connects pre-mRNA splicing and exon junction complex assembly. Cell reports 101 22959432
2012 Human CWC22 escorts the helicase eIF4AIII to spliceosomes and promotes exon junction complex assembly. Nature structural & molecular biology 96 22961380
2016 The truth about the 1st cycle Coulombic efficiency of LiNi1/3Co1/3Mn1/3O2 (NCM) cathodes. Physical chemistry chemical physics : PCCP 84 26771035
2012 Human spliceosomal protein CWC22 plays a role in coupling splicing to exon junction complex deposition and nonsense-mediated decay. Proceedings of the National Academy of Sciences of the United States of America 81 23236153
2015 Human Milk Oligosaccharides and Synthetic Galactosyloligosaccharides Contain 3'-, 4-, and 6'-Galactosyllactose and Attenuate Inflammation in Human T84, NCM-460, and H4 Cells and Intestinal Tissue Ex Vivo. The Journal of nutrition 73 26701795
2011 Unexpected accumulation of ncm(5)U and ncm(5)S(2) (U) in a trm9 mutant suggests an additional step in the synthesis of mcm(5)U and mcm(5)S(2)U. PloS one 59 21687733
2013 Crystal structure of the human eIF4AIII-CWC22 complex shows how a DEAD-box protein is inhibited by a MIF4G domain. Proceedings of the National Academy of Sciences of the United States of America 45 24218557
2023 Solvation and Interfacial Engineering Enable -40 °C Operation of Graphite/NCM Batteries at Energy Density over 270 Wh kg-1. Advanced materials (Deerfield Beach, Fla.) 36 36548193
2020 Structural and functional insights into CWC27/CWC22 heterodimer linking the exon junction complex to spliceosomes. Nucleic acids research 36 32329775
2010 Splicing factor Cwc22 is required for the function of Prp2 and for the spliceosome to escape from a futile pathway. Molecular and cellular biology 35 20956557
2018 Ac2-26 Induces IKKβ Degradation Through Chaperone-Mediated Autophagy Via HSPB1 in NCM-Treated Microglia. Frontiers in molecular neuroscience 32 29662435
2015 CWC22-dependent pre-mRNA splicing and eIF4A3 binding enables global deposition of exon junction complexes. Nucleic acids research 29 25870412
2017 Diabetic polyneuropathy, sensory neurons, nuclear structure and spliceosome alterations: a role for CWC22. Disease models & mechanisms 27 28250049
2014 Exposure to a northern contaminant mixture (NCM) alters hepatic energy and lipid metabolism exacerbating hepatic steatosis in obese JCR rats. PloS one 23 25222487
2022 Identifying surface degradation, mechanical failure, and thermal instability phenomena of high energy density Ni-rich NCM cathode materials for lithium-ion batteries: a review. RSC advances 21 35424548
2019 Interfacial Stability of Phosphate-NASICON Solid Electrolytes in Ni-Rich NCM Cathode-Based Solid-State Batteries. ACS applied materials & interfaces 21 31199108
2021 Stable Electrode/Electrolyte Interface for High-Voltage NCM 523 Cathode Constructed by Synergistic Positive and Passive Approaches. ACS applied materials & interfaces 15 34797642
2016 Loss of ncm5 and mcm5 wobble uridine side chains results in an altered metabolic profile. Metabolomics : Official journal of the Metabolomic Society 15 27738410
2016 Molecular Mechanisms Responsible for Neuron-Derived Conditioned Medium (NCM)-Mediated Protection of Ischemic Brain. PloS one 13 26745377
2022 One Stone for Multiple Birds: A Versatile Cross-Linked Poly(dimethyl siloxane) Binder Boosts Cycling Life and Rate Capability of an NCM 523 Cathode at 4.6 V. ACS applied materials & interfaces 10 35352897
2019 S-containing and Si-containing compounds as highly effective electrolyte additives for SiOx -based anodes/NCM 811 cathodes in lithium ion cells. Scientific reports 8 31575985
2020 NCM 1921, a Mixture of Several Ingredients, Including Fatty Acids and Choline, Attenuates Atopic Dermatitis in 1-Chloro-2,4-Dinitrobenzene-Treated NC/Nga Mice. Nutrients 7 31936050
2023 CWC22-Mediated Alternative Splicing of Spp1 Regulates Nociception in Inflammatory Pain. Neuroscience 6 37838283
2021 Lactoferrin Alleviated AFM1-Induced Apoptosis in Intestinal NCM 460 Cells through the Autophagy Pathway. Foods (Basel, Switzerland) 6 35010149
2019 Asymmetrically coated LAGP/PP/PVDF-HFP composite separator film and its effect on the improvement of NCM battery performance. RSC advances 6 35540032
2005 Ncm-D-aspartate: a novel caged D-aspartate suitable for activation of glutamate transporters and N-methyl-D-aspartate (NMDA) receptors in brain tissue. Neuropharmacology 6 16169022
2023 Enhanced Electrochemical Stability and Extended Cycle Life in Sulfide-Based All-Solid-State Batteries: The Role of Li10 SnP2 S12 Coating on Ni-Rich NCM Cathode. Small (Weinheim an der Bergstrasse, Germany) 5 37936297
2012 MicroRNAfold: pre-microRNA secondary structure prediction based on modified NCM model with thermodynamics-based scoring strategy. International journal of data mining and bioinformatics 5 23155762
2019 Complete Genome Sequence of Salmonella enterica Serovar Enteritidis NCM 61, with High Potential for Biofilm Formation, Isolated from Meat-Related Sources. Microbiology resource announcements 4 30643885
1988 AsnI: a novel class II restriction endonuclease from Arthrobacter sp., strain N-CM, recognizing 5'-AT/TAAT-3'. FEBS letters 4 2841156
2024 Tuning the Interface Stability of Nickel-Rich NCM Cathode Against Aggressive Structural Collapse via the Synergistic Effect of Additives. Inorganic chemistry 3 38470094
2024 Over-lithiated NCM through Li5FeO4 for high energy silicon-based lithium-ion batteries. Chemical communications (Cambridge, England) 2 38845564
2025 Understanding cross-talk-induced anode slippage in high-voltage mid-Ni NCM/graphite full cells. Science and technology of advanced materials 1 40510302
2025 A Trailblazing Quenching Strategy for Simultaneous LiF Formation at Surface and Intergranular Interfaces for Enhanced Stability of High-Ni NCM Cathodes. Small (Weinheim an der Bergstrasse, Germany) 1 40905233
2025 Leveraging Reaction Heterogeneity in Bimodal Cathodes to Enhance Longevity of SiO/Graphite | NCM Full cells. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 1 41298278
2026 Targeting the splicing factor CWC22 induces mitotic slippage through repression of BubR1 expression and CDK1 activity in cancer cells. The Journal of biological chemistry 0 41534835
2026 Unlocking long-term cycling of ultrahigh‑nickel NCM cathodes at high voltage by boron-induced lattice stabilization. Journal of colloid and interface science 0 42107293
2025 Li-Ion Diffusivity Mismatch in Commercial Level High-Ni Single-Crystalline NCM Cathode and Graphite-SiO Composite Anode: Degradation Mechanism and Controlled Charging Protocol. ACS applied materials & interfaces 0 40184479
2024 Tuning the End Alkyl Chain of the Ether Solvent to Stabilize the Electrode/Electrolyte Interfaces in the NCM-Li Battery. ACS applied materials & interfaces 0 38747425
2024 Insights into the Deterioration Mechanism of Charging Ability during Calendar Aging and Cycling Aging of High-Voltage Co-Poor NCM Cathode-Graphite Full Battery. ACS applied materials & interfaces 0 39382455

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